Thanks, for the information, Kenneth.
I'll check the tank tomorrow for any ID information.
I'll only use that tank if I do not need the under-bed side-space for ramps storage. If I cannot used that side tank, I'll look for a fuel tank to go between the frame rails (there are lots of options/configurations).
I'm guessing that the in-cab fuel tank will get me about 75 miles of travel - I'd like 150 miles between gas stops.