In many states, anybody stamping "numbers" might be open to lots of questions of WHY they were doing that. Especially IF the stamps being used were very close or identical to the OEM stamp font.
The FMVSS required that the vehicle's major assemblies and several parts of the body have stamp numbers which could be traced and relate to a particular vehicle's VIN. The first federal anti-theff initiative. Seems like there were seven place on the vehicle "the number" could be? Some on the body were evident (the ones on the core support, innocently placed there) as others could be hidden under weatherstipping?
End result was that if a vehicle was stolen, then stripped, the missing parts could be traced should they later be discovered "somewhere".
Not sure how to trace that stamp number on the warranty block's tag, but there has to be something, somewhere.
CBODY67