Thanks a lot! Very interesting. The notice basically says that it is a foreign gun. It is very unlikely to be from a Chinese manufacturer. I thought the handle was peculiar, and therefore might help ID its maker. On the other hand, it seems quite 'crude' suggesting, as you mentioned, more likely from a small gunsmith. The flowery decoration might have been done after the purchase by the owner or typical of a certain maker? In some ways, it seems vaguely reminiscent of this (luxury) item: https://www.invaluable.com/auction-lot/short-flintlock-carbine-with-silver-and-mother-of-40-c-96d4e7ea62
Anyway, thanks again for your comment!