US Government Specification Field Watch

The revision letter dates the watch, and the markings must agree with it

Each revision changed something checkable. A (1968): plastic cases by Westclox and Benrus from 1970 to 1976, metal by Hamilton. B (1975): introduced the radiation symbol and H3 on the DIAL for tritium, 'Dispose Rad. Waste' on the CASEBACK, and a protective coating on the hands. C (1983): admitted Stocker & Yale. D (1986): five variants including the higher-specification Type 1, a deliberate departure from the disposable plastic watches, made by Hamilton, Stocker & Yale and rarely Marathon/Gallet. E (1989): drastically changed dial fonts and replaced tritium PAINT with tritium VIALS, in plastic cases by Stocker & Yale and Marathon. This gives an examiner a two-way check: a watch marked Rev A carrying H3 and the radiation trefoil is inconsistent, because those markings arrived with Rev B in 1975 — and a Rev E dial should carry tritium vials rather than painted lume.

Revision and Type are separate axes and both must be read

The revision letter tells you the era and the markings; the Type number tells you the movement. A Type 3 is a quartz watch and a Type 1 is a jewelled mechanical held to ±30 seconds a day — so 'a MIL-W-46374' with no Type is only half an identification, and expecting a mechanical movement in a quartz Type is a false finding waiting to happen. Hamilton's own contribution concentrates in the metal Rev A watches and the Rev D Type 1.

These watches were not designed to be serviced

The specification's whole point was low cost and disposal, and many surviving examples have been opened and rebuilt with whatever parts were to hand. A serviced, part-swapped MIL-W-46374 is an ordinary outcome, not a suspicious one. Originality expectations that would be reasonable on a collectible watch are not reasonable here.