That's a nice rifle for sure.
The lock plate looks like a percussion one to me, but it's hard to tell from your pictures. I wonder if you can you see signs on the lock plate or stock to tell if it was ever a flintlock? If so, you'd need to pretty much stretch the barrel, and reconvert the lock back to flint again, to have it look right.
In the end, it depends on what you want your gun to look like, and the bucks to get it done.
John