[swamp rat]

Thats one hell of a typo, i'd look at the frame on the driver side just behind the ft wheel and compair it to the frame vin, and also the vin plate, they should be the same.

Can you tell if the truck is all origional? of the glove box door was replaced i could see why somebody might try that but how to retype it on an old sticker?

I'd also want to verify the title they have also matches and they are legal owners, i'd also contact the DMV or a licensing office and have them run the number as well.

Yes to me it liiks suspicious.