This would appear to be a 1934/1935 Hancock. Movement dated 1934 and case s/n starts with a "5". Case back (hinged) is marked on exterior with s/n, "Bulova" and "10K Rolled Gold Plate".
Picked from a box of trinkets on a crusty leather replacement band at a garage sale today. Moderate plating wear to high points and it feels like the mainspring is bad. Balance shaft / hairspring assy is good, but it won't take a wind. It just clicks and spins when crown is rotated, never gains any tension. Only one of this model I have ever seen in person.