YESSS! All of the above. Plus, this wasn't mentioned yet, how about just one receiver. The SB2 ! That, along with the machining tolerances tightened, would mean you could buy just one and fit any barrel you want to it. Rifle or Shotgun. Mix and Match to build what suits YOU.
BTW, unless they have sold out of them, they still have some of the smooth bore 12ga Tracker I barrels. Open sights only, though.