Let me get this straight. If I understand the OP's question correctly, he's implying there's a rifled "choke" out there that can be used on a smoothbore barrel to impart a spin to a sabot slug so you don't need a rifled barrel? Well, live and learn! I've never heard of that. I need to keep up with things better.
I've only used rifled slugs in shotguns; never a sabot slug. An ordinary Remington "Slugger" in my 26" IC barrel gives me an effective range of about 50 yards on a deer-sized target. I've never had a rifled barrel so I've had no use for Sabot slugs but I've heard that with a rifled barrel and rifle sights they can increase the effective range of a shotgun out to about 100 yards.
I know you can safely shoot sabot slugs in a smoothbore gun but I've heard that their performance in a smoothbore gun is no better than you would get with an ordinary Foster-type rifled slug (if it's even that good good) so why go to that added expense?. But, hey! If there's a rifled CHOKE that you can put on a smoothbore gun that'll impart a rifle spin to a sabot slug - well, heck, I never even thought of that! Where have I been? Tell me more!