I t looks like an over & under percussion rifle but I don’t know how the hammers would work on such a thing. It doesn’t look like a swivel barrel with that hammer on the left side. Guy on left is also carrying an 1878 Colt DA. Guy on right has a Winchester 1873 (not an 1876) but the cartridges look too big for it in that extra belt. The biggest clue to me that guns are props is when there’s no cartridges in the loops, unlike this picture. But if that long gun on left is percussion post 1878, it seems most likely a prop.