What Hungry Horse is saying is that the lock was originally a flintlock, but was never a flint lock on this rifle. The lock had been converted to percussion before being installed on this rifle. So this rifle was never a flintlock rifle.
I agree with that. For one, there is no cut out relief on the stock, behind the breech, for flintlock cock clearance. This gun has always been a percussion as far as I can see. That is how the American guns are made. Maybe the Euro guns are made differently.
Of course, it is yours to do with as you want......
John