For at least 1947 to 1955-1st series, Chevrolet called the information on the truck's door pillar tag the "vehicle serial number". It included, at least, information about the year, the assembly plant location, the series-number/size-designation, and the sequence/serial number for that vehicle. As stated above, no model information was to be found on Advance-Design trucks.

Some states used this door-post-tag code for title/registration. However, the engine code might have been used for those purposes. And, just to confuse us, the same state, in the same year, might have used either code (I have seen engine-codes and door-tag-codes on original titles for 54/55 trucks from both WA and VA). NY will allow either code to be used.