Close, it would transfer as a AOW (any other weapon) on a form 4 for $5. A 12 gauge pistol rifled would be greater than 1/2 inch and be considered a destructive device. Like a hand grenade. And yes, there are some registered. They take all the fun out of blowing stuff up.Because no rifling=shotgun to the government. So a non rifled judge or governor would be a short barrel shotgun.