The galling shown is no problme what so ever...
Just get some emery cloth on a strip, clean up the 'High' spots and run the spindle.
I would be more concerned with the seal surface rust than the galling on the spindle.
See, the wheel bearings have a very large/thick inner race that comes into contact with the spindle,
The actual BEARINGS never touch the spindle, just the inside of the bearing race,
So 'Textured' surfaces aren't an issue as long as the bearing doesn't 'Flop' around on the spindle.
I've used a punch and hammer to 'Peen' the surface of spindles to hold the bearing snugly after they were galled so badly the bearing moved around...
And it was successful!
(I have enough money now that I'm 40 years older to buy a new one instead of reusing JUNK!
But I see NOTHING wrong with the spindle you are showing other than it needing smoothed down with a strip of emery cloth and having the hub seal surface polished up before reassembly.
I've seen guys freak out over rust on the bearing surface, so I take the old spindle home with me when they discard it.
The big 'Secret' is the bearings (proper) don't actually touch the spindle, so perfectly smooth surface isn't a requirement.
Anyone thats seen some of the lousy machine work from AMC should know that!