It is an original , Belgium percussion pocket pistol, probably dates from the 1840's to the 1860's. At least I see what looks like a Belgium proof mark, but your pictures are a little fuzzy, these type guns were made by every European country and the U.S.. Clear photos of all the markings ( rub some chalk into them ) would tell for sure; Also a clear picture of the muzzle end and the area just forward of the Lock,