The no vent windows and different door handles sound like common differences between a '48 and a '54 within the Chevy line.
I've often had to look close to tell the difference between a GMC and a Chevy, even with newer models.
I'd guess they are probably just about identical and would probably work.. but thats just a guess.. you'll wanna know for sure before you have the new cab suspended from a tractor and finding out the bolts don't line up.
