Could this be an original option/accessory or is it more likely a later unit that just happens to work/fit in these pickups? It looks nothing like an original Chevy heater of that era(about 12" or so square with a slightly rounded bottom and has a nice 3D "Arvin" applique on the front of it). Sorry, no pics. The last owner had no knowledge of if it was added later or original to the truck. It works just fine, I just want to know what it is. Thanks!
