Since the 9200 series seems to have been discontinued in 2001, I doubt if they are still making extra barrels, but it is possible. The gun was available with 18.5, 22, 24 (rifled and smooth), and 28" barrels. A gunsmith should be able to find some, or you can try contacting Numrich Gunparts.
If it is a Mossberg, it was made by Mossberg. They did make guns for a number of "store brands".
He would make barrels. Everything was shipped and stored in barrels.
Check with Mossberg customer service for a definitive answer.
Seven barrels
barrels
http://www.mossbergcollectors.org/
A cooper makes barrels.
Coopers
Coopers make barrels.
Sorry- there was than one model 335. One by Marlin, one by Springfield. A 3rd by Mossberg is not impossible- they did make many of the Western Auto guns.
No.
According to "Parker Guns, The Old Reliable" by Ed Muderlak, Parker in 1937 at least one pair of Shotguns on a No. 1/2 frame. Each of the guns were fitted with both 12 & 20 gauge barrels. Each of the barrels were 24 inches. I have no record of the 8/10 interchangeable barrels but I do know that Parker had many request for a 10/12 combination for which they refused because of the extra metal needed to fit the two barrels at the breech, thereby making the gun one to two pounds heavier.