It was standard in 73. 74 they started putting them under the bed. My 74 is saddle tank. This is for Standard cabs. My 73 Clubcab had saddle but filled through the cab. I've had a 75 Cab that was in cab aswell. Its hard to really say when they quit or ran out. None of my 75 up trucks have ever had in cab tanks and I've owned over 40 and that's just in the last 12 yrs