Kees,
I just ran into this post,I believe that these Lyman stocks are American black walnut or, a dark version of European walnut I don’t know of,I always assumed they were American Walnut in the past but never thought about that they are made “over there” which is something to think about,either or , I don’t believe there is much stain to remove,the best you could do is use wood bleach and see what happens.The Lyman stock I have is really dark also and sits waiting for a barrel of undetermined cal. ,probably.54, can’t go much bigger with 15/16” you could always try making a new front sight with a wider or longer base for it by silver soldering one together using brass or copper I’ve made a couple using old keys and a newer one using a homemade copper base with a brass insert for a blade ,you can buy a base on track of the wolf maybe oversized?,I just do things the hard way sometimes, [ Invalid Attachment ] I may make a prettier one later but I kinda of like it’s crude look for now