The pricelists call for three variants, A & B like you mentioned, and C (#38771) which is the one with white gold bezel at $71.50. There is no fourth variant listed. The ads we have do not clearly show the engraved bezel for the 'A'. Are we sure the 'A' variant has engravings? Perhaps it the the plain bezel with a strap; looks plain to me, as the dashes or marks appear to be in the crystal, depicting the minutes track.
As for the crystal, the GS CMX 324-6 covers several models (ACADEMY AWARD Y, AERONAUT, AUTO WATCH C, BRIGADIER, BRIGADIER B, DORRANCE, DOUGLAS D, ENGINEER A, HARRINGTON, PHOTO WATCH); and I have one to spare if you need. Msg me your details.
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C variant ref, photos of a NOS one that came up for sale some time ago:
