Not much into matchlock gun, Have you tried a Google search? Or move this down to " Harley Nolden's Institute for Firearms Research" on this forum.
Here I googled for you...go to this forum:the #1 site in the world for real authentic japanese antique guns
http://www.japanese-guns.com/
Here is one on Gun Broker for $3000
http://www.gunbroker.com/Auction/Vie...Item=257588470
Hope this helps and gets you in contact with like collectors.
Roger