One of the two people who were true Krag experts was Bill Mook. He once compiled a list of possible Model 1898 rifle rear sight possibilities and came up with over 60 variations! Don’t forget the 1898 sight can still be found as original, with rounded edges and even with the flip up Sargeant’s peep.
BTW, the other true Krag expert in my book is Tom Pearce. Always hoped that Bill and he would have produced a book on the Krags, especially the Model 1892 that they compiled an insane amount of data on.