Those early 70's longhorns you can actually see the seam in 'em, too. Also many seemed to have an aux fuel tank door near that part.
Richard
The Longhorn box had an (optional?) integral “tool box” as well, beneath the bed (on the passenger’s side, opposite the aux fuel tank on driver’s side) with a locking door accessible from the exterior. One could carry a jack, tools, flares in there, or whatever.
Dad had a ‘72, C20 Longhorn 2x4 400BB TH400, split-ring two piece rims, aux fuel tank, toolbox. 4.11 gears IIRC, two-tone paint and relatively fancy interior (Cheyenne trimline), cloth bench.
We used that truck on the farm for
many (30-35) years. I should have restored that truck.
It went to a good home.
(edit) It looked like this one, but w/ longer bed and factory wheels.
Later this month, this monstrous Chevrolet C20 long-bed will hit the auction block in Las Vegas with the power of 800 horses.
chevroletforum.com