Your rifle has character. The gun looks to be assembled a long time ago. The lock could possibly have been a flintlock that was converted. The hammer looks like a percussion hammer that was used to replace a flint hammer. If the forend is loose or fragile you can scrape the barrel channel and lay a piece of fiberglass matting in the barrel channel. Brush polyester or epoxy in the channel and re attach the barrel that has been coated with wax or release agent. The next day you can remove the barrel and trim and sand off the excess fiberglass matting and resin. This will stiffen your forearm and allow you to shoot and hunt with this rifle. Put Bambi in the freezer with it! .54 caliber is a great muzzleloader caliber.