sm, you'll need the lever action rifle and a shotgun. In fact, if you load BP in your rifle cartridges and use either a SXS or lever-action shotgun with BP loads, you can shoot Frontiersman (a category that I find VERY cool). Lot's of smoke, lots of cool points, and not a lot a shooters in that category (least as far as I've seen).
While it may be a year or two down the road for me, I hope to shoot in that category eventually.
If you don't have the other guns, don't worry about it. Show up and shoot. Somebody'll let you borrow a gun here or there. Heck, if you show up at my shoot, you can borrow my new '92.