The '47 & '48, GMC 1/2 ton, 3/4 ton,& 1 ton, front bumpers looked like this,
http://community.webshots.com/photo/261298995/261395879JDFozu . The '49-'54 GMC 1/2, 3/4, & 1 ton front bumpers, were the same as the '47-'54 Chevrolet 1/2, 3/4, & 1 ton bumpers. The '47-'54 1 1/2 ton, & 2 ton Chevrolet Commercial bumpers were channel type, with the raised beltline you speak of. The '47-'54 GMC 1 1/2 ton, & up Commercial Bumpers were the channel type, but without the raised beltline. Some Canadian built, "AD" GMC Commercial trucks, were outfitted with the, Chevrolet Commercial Bumper.
