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Authentication notes recorded against catalog references: what to examine, what it establishes, and how well evidenced it is. Every note links back to the reference it was written for.
Interchangeable parts are legitimate — judge the movement and case, not the peripherals
Vostok · Amphibia · Ref. 420
Bezels, dials, hands, crowns and casebacks cross-fit across decades and are widely swapped (Meranom, Murphy bezels, etc.). A non-original bezel/dial/caseback is usually a genuine mod or service part — classify as authentic-but-incorrect / modified, NOT counterfeit, unless the movement or case itself is non-Vostok.
Original and Archive Series reissue share the dial text
Bulova · Oceanographer · Ref. Oceanographer Devil Diver
The reissue reproduces the 666 FEET marking, so the text does not distinguish period from modern. Case finishing, crystal material, movement and caseback markings do. As with several reissues in this expansion, a photograph is not sufficient to establish which one is being offered.
Quick-release hardware separates the generations immediately
Baume & Mercier · Riviera · Ref. Riviera (2021 revival)
The modern bracelet uses a quick-release mechanism at the case join; the 1973 watch does not. Combined with the crystal material and the movement, this makes the generational question straightforward — which matters, because a period Riviera and a modern one occupy quite different places in the market and the design similarity invites conflation.
A dried Aquadura cork seal explains a leaking vintage Mido
Mido · Multifort · Ref. Multifort (1934 original)
The cork element in an Aquadura crown swells slightly on contact with water, which is how it seals. Stored dry for decades it shrinks and hardens, and the watch loses its water resistance. A period Mido that fails a pressure test is very frequently a watch needing a crown service, not a watch whose water-resistance claim was never true. Report it as a service condition rather than as a specification failure.
Cabochon crown
Cartier · Tank Must · Ref. WSTA0041
The winding crown is set with a faceted synthetic spinel (blue) or, on gold pieces, a sapphire cabochon. Plastic 'gem' or a plain crown is incorrect.
Cabochon crown
Cartier · Tank Américaine · Ref. WSTA0018
The winding crown is set with a faceted synthetic spinel (blue) or, on gold pieces, a sapphire cabochon. Plastic 'gem' or a plain crown is incorrect.
Cabochon crown
Cartier · Tank Française · Ref. WSTA0067
The winding crown is set with a faceted synthetic spinel (blue) or, on gold pieces, a sapphire cabochon. Plastic 'gem' or a plain crown is incorrect.
Cabochon crown
Cartier · Tank Louis Cartier · Ref. WGTA0011
The winding crown is set with a faceted synthetic spinel (blue) or, on gold pieces, a sapphire cabochon. Plastic 'gem' or a plain crown is incorrect.
Crown-only operation is the specification — check for absent pushers
Frederique Constant · Classic Worldtimer Manufacture · Ref. Classic Worldtimer Manufacture
The case band should carry no correctors at all. Every function — local time, city ring, 24-hour disc, date — is set through the crown. A watch presented as this reference with recessed pushers in the case flank is built differently, whatever its dial says. This is a check that can be made from photographs of the case profile.
Crown-protecting bridge and lever
Panerai · Luminor Marina · Ref. PAM00111
The signature lever bridge presses the crown against the case for a water-tight seal; its action, engraving and fit are precise on genuine pieces.
Faceted crown with spinel cabochon
Cartier · Santos de Cartier · Ref. WSSA0018
The crown is seven-sided and set with a faceted blue synthetic spinel; a domed glass 'cabochon' or a plain crown is incorrect.
The small crown is the identifying feature of this reference
Seiko · 62MAS · Ref. 6217-8000
6217-8000 carries a noticeably smaller crown than the 6217-8001 that replaced it. Because the case numbers differ by one digit and the watches are otherwise close, a large-crown watch offered as a -8000 is either mis-described or has had its crown replaced with the later part. Read the case number off the caseback and confirm the crown matches it; do not accept either on its own.
A blank display is normal until the button is pressed
Bulova · Computron · Ref. Computron LED
LED watches of this era show nothing at rest. Press the pusher and the digits illuminate for a few seconds. This is the single most common misunderstanding about the model, and it produces a false conclusion — that the watch is broken — on watches that are working exactly as designed.
Crystal condition carries the service history here
Mido · Commander · Ref. Commander (monocoque)
Because the movement is accessed through the front, every service on a monocoque watch involves removing and reseating the crystal. Crystal fit, seal condition and any damage to the case's crystal seat therefore tell you what a caseback and its gasket would tell you on an ordinary watch. A poorly seated crystal on a Commander is both a water-resistance problem and evidence of past work.
Crystal thickness is part of the specification and is measurable
Certina · DS Concept · Ref. DS (1959 original)
The DS crystal is deliberately thick, and thickness is one of the few specification claims an examiner can check with a gauge rather than by comparison. A DS-marked watch fitted with an ordinary thin crystal has been re-crystalled with a generic part — a common and understandable repair, and a real loss of the specification the turtle claims.
Sapphire from 1962 is unusual and is part of the identification
Rado · DiaStar Original · Ref. DiaStar 1 (1962)
The DiaStar was fitted with sapphire at a period when acrylic was standard. An early DiaStar with an acrylic crystal has been re-crystalled with the wrong material — a service finding, common enough, and one that also removes the scratch resistance the watch was sold for. Test by touch and thermal behaviour rather than by looking: sapphire feels cold and rings differently.
Sapphire on the reissue, acrylic on the original
Doxa · SUB 300 · Ref. SUB 300 (reissue)
The simplest physical separator between the generations, and one that survives a re-dial and a bezel change. Acrylic is warm to the touch, scratches readily and can be polished out; sapphire is cold, unscratched and rings differently. A period SUB with a sapphire crystal has been re-crystalled — possible, but it should then show other period evidence.
Sapphire, not acrylic
Rolex · Explorer II · Ref. 16550
The 16550 introduced the sapphire crystal; an acrylic crystal indicates a 1655 (or a wrong service part).
The chapter ring is printed on the crystal, and reproductions exist
Bulova · Accutron · Ref. Accutron Spaceview
On a Spaceview the hour markers are printed on the underside of the crystal rather than on a dial, because there is no dial. Reproduction Spaceview crystals are readily available — they are what a conversion needs — so the crystal is not evidence of anything on its own. Its condition can still be informative: period crystals show age, and a pristine modern crystal on an otherwise worn 1960s watch is consistent with a recent conversion.
The domed crystal is a structural consequence, not a style choice
MB&F · Legacy Machine · Ref. Legacy Machine
A balance suspended above the dial needs clearance, so the crystal is domed high. An LM-style watch with a flat or shallow crystal has no room for the construction it claims. Judge the case in profile.
The tactile function is a live test a counterfeit rarely passes
Tissot · T-Touch · Ref. T-Touch (tactile crystal platform)
Activate the touch mode and try each zone. Genuine watches respond to a light touch on the crystal at defined positions; counterfeits either omit the function entirely behind a printed crystal, or implement it so poorly that the zones are unreliable. This is one of the few models in the catalog whose primary authentication check is a functional one rather than a visual one, and it is correspondingly hard to fake.
'UNIQ' branding, 7-shaped crystal and 'U'-tipped chronograph hand
TSIKOLIA · UNIQ Seven Chronograph · Ref. Seven-BB (UNIQ, 2015)
The dial and strap carry 'UNIQ' branding (not 'TSIKOLIA'), the crystal is cut to the outline of the number 7, and the central chronograph hand ends in a 'U'. These distinguish the UNIQ-era Seven from the modern TSIKOLIA TW-7.
1853 is a date, not a model, and its printing quality is informative
Tissot · PRX · Ref. T137.407.11.041.00
Every modern Tissot dial carries the founding year under the wordmark. Its presence proves nothing. Its EXECUTION is useful: on genuine dials the four digits are small, even and sharply defined, and on counterfeits they are the first element to thicken or smear, because they are the smallest printing on the dial. Judge the printing, and ignore the number as an identifier.
50 Atmos is a pressure rating, not a reference
Squale · 50 Atmos · Ref. 50 Atmos
Fifty atmospheres is roughly 500 metres, and the marking states the specification rather than identifying the watch. A listing quoting 50 Atmos as the reference has quoted the depth rating, and the actual reference is a different thing that still needs establishing.
A jewel count on a -6002 dial is a North American dial
Seiko · Chronograph 6139 · Ref. 6139-6002
North American -6005 and -6009 dials state '17 JEWELS' beneath the hands and read 'AUTOMATIC' rather than 'CHRONOGRAPH AUTOMATIC'. A -6002 case carrying that dial has had a dial change. Both parts are genuine Seiko; the combination is not the one the case left the factory with.
A large moonphase disc shows its own quality
Arnold & Son · Perpetual Moon · Ref. Perpetual Moon
The disc dominates the dial, which means its finish, the crispness of the moon's edge and the depth of the sky field are all displayed at a size where flaws are obvious. Printing or plating defects that would be invisible on a conventional aperture-sized moonphase are plainly visible here.
AOPA vs Breitling logo by period
Breitling · Navitimer · Ref. 806
1950s–60s dials often carry the AOPA winged logo; the twin-jet 'B' logo appears later. Logo must match the production window.
Applied Arabic numerals and leaf hands
IWC · Portugieser Chronograph · Ref. IW371605
Genuine Portugieser dials have crisply applied Arabic numerals, a fine railway minute track and slim feuille hands; printed numerals or clumsy hands indicate a fake.
Applied numerals are judged on seating and finishing, not letterform alone
Franck Muller · Vanguard · Ref. Vanguard
Where numerals are applied metal rather than printing, look at how they sit: genuine applied numerals are seated cleanly and consistently, with uniform finishing across every character and no adhesive visible at the edges. Counterfeits show inconsistent height, visible glue, and finishing that varies from numeral to numeral. The letterform check still applies, but the seating is the faster tell.