Yes and no. The yes comes from simple fact, if the projectile can move down the barrel, it can be fired. I've seen .221 Fireballs fired out of a 7TCU barrel. The no is because you cannot do it well....
The model number is stamped on the right side of the receiver on many Stevens products.
Look in the yellow pages for gunsmiths.
On website GunsAmerica has one for sale for 225. Unknown what condition yours is in or the one for sale.
Yes