If the truck has been registered in CA in fairly recent years maybe they use the VIN number. Originally the trucks (at least in CA) were registered by the engine number. My 1952 hadn't been registered for 24 years when I acquired it. The pink slip still used the engine number as the ID. My truck did and still does have the VIN tag but that number was not originally used. Unfortunately my truck engine had been replaced with a 216 from 1953. This meant I had to have it verified by the CHP. They did not require a running vehicle but did require it to have everything required to run installed (i.e. must have engine, trans, etc. installed). I don't think they use the best and brightest at the CHP offices to do these checks. Despite having extensive documentation and info showing what years engine numbers were used in what year it took about a week after the initial inspection before I got the all clear to go to DMV to register the truck in my name and put it on non-op status. When they finally did this they did use the door VIN info for the official numbers.
