I'd leave it as is and enjoy it...Plenty of higher grade examples out there. Some of my favorite vintage firearms have that "used but not abused" appearance, and I often wish that they could tell me the tales of their former adventures.
Amen to that! I've got a handgun that was made right around the end of World War 2 - I joke with friends that "It's my '45" (year not caliber ;-). It's not super collectible, and had seen enough 'real world' use that some previous owner had actually spray painted it black. I cleaned off the paint, and got lucky: there was 'old school' bluing underneath in most places, along with a few areas that had worn down to bare metal, but no rust. I thought about cold bluing it, but the wear is part of the story!
Bought some new mesquite wood grip panels for it, from a nice gent down in Texas, and picked up a few extra factory mags at gun shows. It got a brand new recoil spring (rest of the springs were good); feeding, extraction and ejection are reliable, the trigger works for me, and (most important) it's fun to shoot! To me, it's pretty as a picture - form follows function! It's the only firearm that caliber that I own, but I enjoy loading for it, and actually back the loads off a bit, so it will probably outlast me by a couple hundred years (nothing wrong with a traditional, all-steal firearm). I've got a period flap holster it rides in when we're out in the national forest.
Nothing wrong at all with "used but not abused"!