Does the shifter have the reverse lock-out lever?
Does the truck have 6 wheel lugs or 8?
Are you familiar with the 41-47 truck ID guide here
https://www.stovebolt.com/techtips/art%20deco/index.html ?
Did the truck come to you with a valid title?
Does it appear the frame has been shortened? Does it have a short bed (~6.5') or long bed (~7.5')?
Post some pics of the whole truck.