i was looking and looking for a vin number on my blaster. I couldnt find it so my dad took one look and found it on the motor lol. So its a 92 instead of a 91.
Or it could be a blank frame. like a replacement frame from the factory. I know a guy that has a blaster with a blank frame. When he sand blasted it to re-paint it there was not a mark on it where the vin should be