Contact Chris Showler at Double Eagle Trading in Nevada for just about anything you need to know about Nikko shotguns.

cshowler@gmail.com
Phone 775-882-9739

I don't know if he still has his own website, but he lists a lot of guns on Doublegunshop.com at
http://www.doublegunshop.com/showler.htm

Nikko is the brand name for Win 101s marketed out of the U.S., and a lot of the parts are interchangeable. When I needed a new butt stock for one of my 101s, Chris sent me a Nikko stock and it was a perfect fit. The subject gun is marked "Special," so may not be a standard production version. Probably similar to Miroku's practice of having a bunch of "standard" models, but there are always odd or special versions that pop up.