If you are OK with the outside wear check the rifling. Outside wear is not necessarily an indication of shooting wear. Kept an old Topper 12 gauge wrapped in a rough wool blanket in the trunk of my care the whole time I was in the Army. Almost all the bluing was gone but that shotgun didn't have over 10 boxes of shells shot through it. Next make sure it locks up without any play in it. Break it open and slam it shut several times. Make sure the transfer bar is working. It should make the pin stick out of the breach face when you lower the hammer with the trigger pulled. It should not if the trigger is not pulled. Almost forgot, make sure that barrel is on an SB2 frame. Can't trust anything anymore.
Darn, you're fast Tim. There wasn't a single reply to this thread when I started typing.