Yes, I see the pictures now. Very nice rifle you have purchased. You should enjoy this Krag for years to come. One to be proud to own and pass down to the kids.

There should be no problem removing your sight screws. Very rarely are they rusted shut so tight that they are difficult to remove. The condition of your Krag rifle is good enough that I would think they should be easy to remove.

Make sure you have a proper fitting screwdriver that has nice sharp edges to the blade. Clean out your screw head slots if they are dirty to get a good "purchase" or good bite to the slot. Turn slowly and they should be easy to remove. You don't want to do what thousands have done before you and force a dull screwdriver into the slot and turn quickly and bugger up the screw.

If it is tight, drip some thin penetrating oil on the screw head and threads and let it sit overnight. Should be fine.

Also, some of us have carefully drilled out the M1902 rear sight peep hole to enlargen it enough to be able to easier see through it. That is an easy thing to do that can give you a better sight without having to change the slide. There are options. Your approach is one way to do it. Some of us like the M1901 rear sight better and find it easier to see through for longer distance shooting.