stepside beds were the same from around 53? I think until they stopped making them around 85. They aren't overly common but you can still find them, they make reproduction fenders and tailgates for them.

Other then rust, the common issues are they will go forever. I have a 69 and 71 parked out in the weeds that will both start and run if I take a battery out to them. They are really simple and basic, but dependable.