Here's a couple of pics. Regarding the red arrows, if I lay a straight edge on that plane , it is dished 2-4 thou and I can see daylight under the straight edge in the middle. The white arrow is pointing at a scratch mark which is the place where it comes free, forward and rearward of that area its OK.

Because the rifle is otherwise so good, with matching serial on the bolt, I'm inclined that the owner should try a few bolt heads and/or try building up the groove in the bolt head. Would there be any reason not to do this?
thanks.