Probably a model 3600 if it's a GMC.
Excuse me but 3600 is a designation for a ¾-ton Chevrolet. This is a Chevrolet but not a 3600.
if you find any numbers on the badges on the sides of the truck, let us know
Numbers weren't used on the sides in '47 so there won't be any.
Best bet to ID it is the serial number of the cab. I'm guessing it's a 4100, 1½-ton, or a 6100, 2-ton.