Krag rear sight help

I have two 1898 Krag rifles, one has a 1900 cartouche and the other has a 1903 cartouche. They both appear to have the 1898 rear sight but the elevation slide lock wheel is broken off of the sight on the 1900 rifle. I would like to replace the slide with the one from the 1903 rifle because I don't know of I will find another one and the 1900 rifle is in very nice shape with a perfect bore and the 1903 is not that nice and has a bad bore. I would switch out the complete sight assembly from one rifle to the other but I like the rotating peep on the 1900 rifle. I have a couple of options the way I see it, either replace the whole slide or just the lock shaft.

The 1900 sight is the bottom one.
https://www.milsurps.com/images/impo...10/00489-1.jpg
https://www.milsurps.com/images/impo...0/001114-1.jpg
https://www.milsurps.com/images/impo...10/00862-1.jpg

Do I drive out this pin to remove the slide from the elevation bar?
https://www.milsurps.com/images/impo...10/00673-1.jpg

Or should I drive out this pin to release and change out the locking shaft assembly?
https://www.milsurps.com/images/impo...10/00578-1.jpg

You appear to have 1898 sights modified to the standard of 1902. The one with the peep is the later variety of the two. Neither is original to your 1900 dated rifle. Just buy a new sight, either 1898 or 1902. It's easier. Or just buy the whole slide and eyepiece. They're available. Fixing these sight is hard, though not impossible.