I'm no expert, but I've been told by one that the Turks got into making repro's of European guns of the 1600's and 1700's sometime in the 1800's. I guess the style just caught on. There were, as you might expect, good ones and bad ones. The good ones I think are sold these days as "19th century reproductions" without mentioning Turkey (it can be impossible to tell where they were made, of course). The lower quality ones are sold as Turkish or Middle Eastern.
There are usually Middle Eastern design elements that give them away, like on yours, but some are faithful copies and only a trained eye can spot them for what they are.
Some makers seemed to just pick the ideas that appealed to them, from whatever era or area, so you see mixes of French German and English design elements.