George:
That's definitely the Body Serial (VIN) for a 1946 second run half ton.
Piece of cake.
I dunno what to tell you about the VIN plate and the Highway Patrol. Does the DMV know that it's missing? In Michigan, they don't look at it -- even if it's an out-of-state truck. (They do, however, require a VIN inspection to get the title changed to the body serial from to the engine serial.)