"Do you think that a GM factory put that "ID" on the frame, or do you think it was a dealer or the California DMV?"

The 1955 specifications manual does not mention an ID code being put on the frame by GM. Is a frame ID specfified in 1955 GM documentation?

http://www.1954advance-design.com/chev-specs/1955-2nd-Chevrolet-t-ser.pdf

http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0serial1.htm