It's not everyday I read these forums and find my own truck in here! mphudak, I do not know whether my truck was original from the factory that way, I kind of doubt it. The story I have is that it was originally purchased by the California forestry service, and I assume that it was modified for them. Yes, it had a gas tank on each side, and a filler tube on each side as well, so the tank would have had a filler on the opposite side from usual. They were plumbed into a "t" valve, and there is a knob in front of the drivers seat which set the valve and controlled which tank it was drawing from. Unfortunately, the previous owner removed the extra tank, but the plumbing, "t" valve and valve control are still there.
I assume by now your 'burb is here in town? I'll have to give you a call and check it out.