Originally discussed here http://www.vikingsword.com/vb/showthread.php?t=19810, the origins of this one have not in my opinion been narrowed down.
The stock is more of the shape seen on Ottoman arms but the side profile is wrong for them.
I really would like to find out more definitely where this particular matchlock comes from.
Stu
Stu, I dont know of many Ottoman matchlock images to compare against but here are two.