The windage adjustable sights were staked.* Re-staking only requires a center punch; set it on the receiver next to the sight slot and whack it, putting a little dent in the metal that will hold the sight in place and keep it from moving sideways.
*FWIW, the original flip sights were just driven into the slot but not staked. So that is a way to tell if a carbine has been "restored" by removing the later signt and installing a (real or repro) flip sight to make it "original".. If there are stake marks, the gun had had a windage adjustable sight installed.
Jim