I am actually a licensed salvage dealer in Texas. They are very particular about late model stuff and everything has to be documented. They don't really about vintage stuff unless they have reason to believe that something is stolen. Everyone of my over the road trucks was reconstructed from salvage. I have documented where the components came from. Late model trucks have the vin stamped on the frame as well the door jamb. Quite often the cab and frame were not born together. Prosecution must prove fraudulent intent. This is a difficult task for the prosecution if there was no fraud involved.