What might a fella expect to see if requesting factory letters on 99’s from 1933 – 1958 ?

Savage pistols from 1910-11 and 1920 ?

I have a 1904 Boys rifle from 1904 I’d like to letter also . I was told it was at the Worlds Fair either at the Ozarks shooting gallery or displayed at the booth . I'd like to find out for sure .