@TrickyDick
Just polish the bore with JB Bore Brite and it should be fine.
Several of the M-N's I fire lapped the bores, and they shot really good.
The Fine Pits are not the problem, as long as the sharp edges of the pits is not causing a resistance to the bullet going down the bore.
It ain't going to shoot like a Prestine Barrel, but it will be better than what you have either way.
Of all of the M-N's I have owned, only three had Excellent Bores, and they were all Finn's.
But some of the ones I had , had Black Bores and were still calable of 1 1/2 " groups at 100 yards with Handloaded ammo tuned for that rifle.
When you slug your bore, you should be able to see how the pitting is effecting the bullet.
Slug the barrel before , and then after polishing and see if there is an improvement.
I will bet there is.