It depends on the main reason for wanting the guns. If it is for the pleasure of owning & keeping it & shooting occasionally, I'd go for the older two barrel gun. If i was going to seriously hunt more often with it & expect to shoot say pigs at 150 yards etc., I'd go for the newer gun.

I would make sure that both guns are good working order & do not need any repairs etc. I would also be prepared to learn about black powder loading & cleaning before I make my decision.

Good luck. Sounds like a fun venture.