They do seem to be too regularly shaped to be damage.

by Hoot , Diversityville, Liberal-sota, Monday, April 25, 2016, 07:09 (3476 days ago) @ Hobie

The annular ring can be seen on mil-surps fed a diet of corrosive ammo. There also appears to be a slight raising around the firing pin. A quick image search for Arisaka bolt faces didn't turn up anything looking like this...and really didn't turn up too much of anything else.

I would be thinking strongly about repair or replacement. I assume it could be TIG welded and resurfaced by a fellow with talent in that arena. Not many replacement bolts out there and you just might end up with something worse and $100 poorer.