Ethnographic Arms & Armour - Ottoman Flintlock from Sudan

I was given this piece recently by the family of a friend whose Great Grandfather was in Port Sudan during its construction around a century ago and it is thought that it was collected there along with a Kaskara, some spears and a bow.

I think it might be Ottoman - there are blank cartouches on the barrel which are for inscriptions, I think. There is a mark - a letter "A" struck twice on the barrel - perhaps it was produced in Europe for Turkey? I also notice that there is something on the lockplate which might be an inscription and that there is some metal - possibly copper - inlay on the stock.

I would be very grateful if any members might have any ideas about its origins.