This is the small round head 1-5/8 inch long Hurd key used on 1932 Ford door and ignition locks. The code number was stamped on a metal tag on the key ring, not on the key. The key is bright nickel plated brass construction.
Later 1930s V8 Fords used keys with larger heads having a variety of unusual shapes, but not round, except for a large round head spare tire lock key. There is also a similar round head key blank, but having a longer overall length, which was used for mid 1930's Chevrolet spare tire locks.
Back side view.