I bellieve your shotgun is of a English make. If so i will give you a web and email of a person whome does nothing but research english firearms. The website is
www.firearmsresearch.co.uk and the email is
[email protected] They do charge for this service,but if im right you never know how much its really worth,unless you check up on it as you,ve wanting to do. Her name is Susan Boothroyd. Hope this helped you some. I might be wrong but it wouldn,t hurt to find out. Good luck vangunsmith