Phil,
Spanky might know the answer.
However, that illustration is from a 1954 Chevrolet Truck GM/Chevrolet document. I’d guess that a GM factory made the cab/truck (but, I bet they did not make many of them).
Years ago we discussed it here and/or on the OldGMCtrucks discussion board. One member said the a big crew truck like that was useful in oil fields (drillers and maintenance crews).
