Hello A5TimberRat: Early 20ga guns had a 2 1/2 inch chamber, it was the 16 ga. that had the 2 9/16ths chamber. This vintage is sort of a "catch 22" gun. Meaning if it still is original and the chamber and ejection port haven't been opened up, it's not worth what the later 2 3/4 inch guns are. If the chamber and ejection port have been opened up, then it's no longer original, and again not worth what the later guns are worth.
A lot of them were opened up, but the gunsmith failed to mark it. Some would use a "steel stamp" and if Winchester did it they would run the roll die on the barrel. Are you sure it hasn't been opened up?
you mentioned that it's in "rough shape" that could mean so much. If the gun has pitting, and I'd say in more than 10-15% of the gun, you will actually be saving the gun by restoring it. If the gun has severe pitting, greater than 35% or so, you may not be able to save the metal. The pits could be too deep.
I try to buy Md 12s that are the first or second year of major changes, and yours would be that, meaning it should have a "grooved receiver top and the 14 groove forearm". About 4 years ago I ran across a first year 20ga. with the "new 28 inch barrel", that was all original in about the 85% condition range and paid $400. for it. It was still original with the short chamber, so I just went out and bought a flat of short shells and use it about once or twice a year. It's a sweet gun.
Anyway, yes you probably could sell it and double your money at a minimum. But without actually seeing how rough it is, I really can't tell or suggest what you should do. Is there anyway you could post pictures, or email me some at
[email protected] ?
Regards Dave