Early AC Question?

[karl]

I bought a 75 c10 that was sitting in a guys yard since the 90s. No engine. The truck had AC hoses coming from the firewall, a condenser/dryer by the radiator and what looks like a retro fit dash control with 2 small vents. No suit case on the firewall so im guessing the evaporator is under the dash. Did GM have factory air setups like this or would this be aftermarket? Looks like it is as old as the truck.