I'll have to look next time I visit... taking door panels off is a pain.
BTW, doing some digging on the net, I read an article on the Jim Carter Antique Truck Parts website stating: "To draw attention to this larger pickup, the Chevrolet division included “Longhorn” die cast chrome letters secured at the rear of the sides. GMC’s designation was “Custom Camper” and these letters are on each door above the chrome handle, not on the bedsides. To make it a little confusing, GMC also used these Custom Camper emblems in the same location on their heavier 3/4 ton, 127" wheelbase pickup, with leaf springs."...
The plot thickens...