Hi Rick,
Not an expert gun lobbyist
, but having read the old comments on this piece, I truly feel that it is NOT a copy. I have a VERY similar piece in styling (but not the markings or length, of course)that was percussion and came from an old collection, ca. 1850. I would agree with the forumites who suggested India just based on some clues. #1 The designs do distinctly look more Indian than Islamic. Most of the Persian types had more elaborate and distinctly decorative butt caps than your model. #2. The length! Very impressive and reminds me of at least two other examples I've seen in auction catalogs listed as Indian sub-continent. Sorry, I no longer have the exact references. Because of the relatively late usage of earlier-style firearms in this region of the world, despite it being flint lock, I suspect it to be more mid-19th century judging from the wear/patina, but this is just my two-cents. On to the real experts...