I doubt Kahr would refinish the slide, probably just replace it if you wanted. (not for free).
There are lots of places that could refinish if you feel the need. Reblue or cerakote, or other finishes.
I don't mind character wear myself but I do like to keep my guns looking nice. Kind of a personal choice, long as it's running good, there's no immediate issue.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."