This one is a 1931 Bulova and that's about all I know about it. The movement is a 9AF and it has the "shield", "omega" and "F" stamped on it for date codes. The crystal is not the correct one. It's the right size, but doesn't have the right curvature. I think the correct crystal is a G-S MX458, but I didn't have one. Something I have observed that has me puzzled, Bulova likes to use "666" a lot in serial numbers. Even some of their water-proof models say to a depth of "666".
Nothing stamped on the outside of the back and nothing to show case metal content.