Re: front sight?
You are correct, the tenon size is critical. I had .the front sight replaced on my GI WWII Champion and if I remember correctly, mine had a "medium" tenon. The gunsmith took a wide tenon and filed it down to fit. I bought those replacement sights from King's. It was a three dot system.
The only thing needed for evil to exist......is for good men to stand by and do nothing!!!