He said it comes with another barrel. I assume different choke because its not rifled.
As has been stated, its hard to tell about the barrels without further explanation but just because the spare bbl is not rifled does not mean it's not a slug bbl.
Many old 1100 owners had a field bbls. (usually a longer bbl. with bead front sight) for small game hunting and a smooth bore slug bbl. (shorter bbl. with rifled sights) for deer hunting.
FWIW, the smooth bore slug bbl's shoot rifled slugs....
...and yes, since I love the 1100, I'd buy it in a heartbeat @ $400