Tales, I think the conversion would mean the original flintlock plate would have been removed and a percussion one installed in its' place. The fit of the metal to wood around the lock plate looks sloppy which would have been much tighter with the original flintlock plate. While the original flintlock hammer could have been removed and a percussion one installed along with the percussion nipple and drum, I do not see any wear from a frizzen spring. I would think wear would be evident on the lock plate from the frizzen spring.
A very nice pistol Texasbadger, even if it was converted eons ago. I really like the face on the butt. If you do ever take it apart, a maker's name could be on the back of the lock plate also. At least the maker of the lock plate.