Well they had to have been machined for those seals to fit. Sometimes when those seals are installed they can get crooked on the guide, which I can take a guess someone could have used a socket to correct that & it pinched the top.
2.
Other thing is guide height and possible keeper contact but by the looks of the photos I'd guess a variation of the 1st part.
I always take a file to the stem directly above keeper grooves because usually there's burrs or something, that gets filed down smooth again
(don't remove too much).
I never use those plastic seal installers deals unless I am installing the hard 100% Teflon seals.
Because it's necessary with the tension rings.