Tim, I doubt that it is factory. The factory tanks were usually rectangular. The one you show is what a dealer would have installed on a truck to rig it as a truck tractor. The one you have is a lot thicker than the side mounted tanks that came from the factory on a cab and chassis or bob tail. Back then the ICC promulgated the few safety regulations we had. These tanks were thicker metal because truck tractors were so vulnerable to jack knifing and when they did, the landing gear would crush the tank. And they were not protected by the truck body.The regulations after 1973 incorporated some of the ICC language that was law before 1973. These are the current regulations. The tank that you show could very well be a Snyder tank that a dealer would have installed on a tractor, but a customer may have requested it on a bobtail.
