Those Spanish made rifles with the two piece stocks that meet near the rear sight were offered in Flint, percussion and convertible with two locks, drum and nipple and touch hole liner.
Dixie at one point offered their cub and some other guns that way.
For some reason they suggest that if you wanted to add the conversion later that you start out with the flint set up.
I keep hoping I will find one of those likely Jukars in a yard sale with a flint lock in place. I found the percussion one I have at a yard sale for twenty bucks. It looked awful and I was told was far from accurate though two deer had been taken with it at bow hunting ranges (less than 40 yards) I got some .45 cal ball and old buffalo bore bullets of the same caliber with it.......imagine my surprise when it turned out to be a .50! I just think my hang it on the wall gun would look better with a flint lock. I disguised the mating plates between the two stock parts with a wide leather band that holds deer teeth and such to give it a more AmerIndian look. I keep considering adding brass tacks, wire and copper inlays but then think it looks just fine. It was a fun project that I did not worry about messing up. Refunished the wood, stripped the blue on the barrel and cold Browned, pulled the breech plug to inspect the bore and clean and polish the same. Put the sights back on correctly and took some of the sharp edges off the cresent buttplate. I have even considered bidding on the occasional Jukar flint pistol in the hopes the lock plate might interchange, but folks always bid them up to more than I want to waste.
-kBob