I think it has the Cheyenne interior package too,my '72 K5 had similar (but different) door panels as this truck, with the "scroll" and woodgrained inserts---
---when its doors were stolen back in '84,all they could find locally was some decent pickup doors,and only ONE GM dealer somewhere in OK had the last Cheyenne door panel for the passenger side left in existance ,when I had the truck fixed at a body shop--they had to lop off the window frames and back then,trying to find the rubbers that go on the door post was about impossible..
I'll second the notion that altering this from its original "build" would be a sin!..
The only other GM factory camper similar to this one I have seen was owned by a guy who set up to sell stuff at a swap meet in NH we were set up next too--he sold old auto sales brochures..had a '66 GMC C-30 with the camper made right to the cab so it was a "walk thru",it had a factory 427 big block ,A/C with a SM420 trans,dual rear wheels,with tall tires,I think they were 17.5" rims too...I thought it was the coolest "motor home" ever!..