If you look on the side of the barrel up near where it meets the frame there should be in writing something telling you that it is a rifled barrel.
If it is a slug barrel it should have a set of rifle sights, but they can put them on smooth bores as well, you can take the barrel off the gun and looking down the tube and you should see the spirals running the length of the barrel.
Scroll down to the bottom of this link for a pretty varied list of barrels for the 1300-1400.
http://www.walkerarms.net/winparts.html