Back in that time period, when a truck was wrecked or deemed too worn out to use, they scavenged parts off of them, often using the frame and running gear and building their own cabs. That is how Freightliner came into existence. Consolidated Freightways was one that used old frames and running gear and built new aluminum cabs for them. Each truck was hand built. They had to stop production during the war because all the aluminum was needed for airplanes. In fact, the US Govt bought all the aluminum Consolidated had during the war. After the war, Consolidated went back to building cabs for their trucks, and others seen them and they wanted some too, so Freightliner was spun off as a new company to build aluminum cab trucks.
I figure Texaco probably did the same thing, when those trucks were considered obsolete, they probably parted them out, maybe even scrapped them for the war effort.
Consolidated Freightways went out of business in the early 1990's. By then, Freightliner had been bought and sold several times and now is a part of Diamler Mercedes Benz.
I have seen some military tankers that were close in design to the Texaco ones. I think they use them for re-fueling aircraft. I don't know if they are a copy or not.