Chinito Quan,

To save Cletis from having to respond/clarify/re-state, there were no GM/Chevrolet codes stamped into the frame on AD (Chevrolet Advance-Design, AD, A-D, 1947-1955) trucks. The truck in question looks like it is a 1950 Chevrolet truck?

Earlier and later years are another matter. GMC is another matter.

It is, however, quite possible that some states put a code on the frame (like California) but it is not clear if CA A-D trucks with frame-codes had the code placed on the frame by CA-DMV when it was new or when it was re-titled in a later year.