I think the copper plates were an effective way to fix the problem. The screws have held up fine on rifles I've examined and Lithgowicon must have been satisfied with the design considering they continued with the practice during the 50's.

Nice gun bear. I'd be happy to have a 1915 lithgow with butt and forend from new manufacture. Good chance the dial plate has had the post or boss ground off and this was someones effort to restore the volley sight.