Guy's; I'd say leaving it as it is is like ' closing the barn door after the horse is runt oft '.
5 K to rebuild is crazy.
Personally, I'd cold blue it, oil it up and shoot it. Or not, your call.
Can't ' unring the bell ' to leave it untouched, I'm guessing it's seen some steel wool or Emory cloth already.
I've had antiques that someone sanded to bare steel; a commercial custom re-blue looks just like what it is, a rebuilt firearm.
Cold blue is easy, cheap and in instances like this...relatively non-invasive. And you don't have to sigh and shake your head everytime you handle it. It wears relatively easy so you can distress it for a worn Patina if you'd like.
IMO, this is not an in-the-white carbine. It looks like a well meaning ( but sadly ill-informed ) individual tried to take it to bare steel.
Don't do any more damage, by any means. But a cold blue wash wouldn't hurt it; christ if you don't like it, about 2 minutes with steel wool and you are back to where it is now.
At least it'd hide the Emory cloth marks.
IMO, of course. Purist's will throw their arms in the air and cry " No, think of the children! " but this one's been dycked with. Can't change that fact, no matter how sad it is.
My brother in law got an original 1897 Winchester reblued ( properly done) and it looks like spinners on a Model 'A'
And I'm of the opinion that case hardened steel looks great; but it's like turquoise jewelry on Women...Too much, just too much!...always overdone.