'55-'58 actually, although GMC did offer a simlar truck up to '59. The best way to describe it is that it was the Nomad of the truck line. Limited production (aorund 5000 in '55, progressivly less each year after), they were mainly loaded trucks, usually with most, if not all of the factory accessories, big window cab and chrome trim was std on them. As far as the body, it's the bed that's different. The sides are fiberglass, however, those sides are mounted to essentially the same box as a std truck. The tailgat is different, having provisions for latches, retactor cables, and a fiberglass cover. There is also an enclosed spare tire carrier under the bed, and it uses a different bumper (with an opening center section to access the spare) than a std truck.
