Some 3500's did come thru as a single rear wheel. But they were mostly cab/chassis. Most of them wound up with some sort of work body on it. My town has 5 99 3500 single rear wheel,CTD. They all have utility bodies on them. AND YOUR DAMN RIGHT I AM WAITING FOR THE DAY THOSE SUCKERS GO UP FOR AUCTION. LoL!
As far as a sport model in a 3500? Rare indeed, around my parts anyway. Most surely though would be a dualie, with either a gas or CTD engine.