Finally got an old pickup truck!

They got away from the seat tanks completely a year or two later. Do you fill both tanks from the same hole? I saw a 72 once with two tanks but only one gas cap, there was a Y in the fill tube and you just reposititioned the nozzle to fill either tank.

very nice truck, you did well
if you shop at RockAuto be sure to register that truck for their Manufacturer Close Outs, I see brake and suspension parts listed frequently for my '83 D150 at great prices.

Your 1972 was the first year of the third generation of the Dodge D Series trucks.
There were occasional sheet metal and dash changes and engine updates, but the basic DNA went from 1972 to 1993.