I have seen this sort of steering tube damage several times. It is caused when the tap washer wants to turn with the nut, when undoing it. Generally a little wire brushing and, perhaps, some smoothing with a smooth file is all that is needed to get it all good enough to use and without any added danger.

Perhaps there are other issues that my old eyes can't see. Were it my fork, I would give it a try. I would also contact the seller and let him or her know that the fork arrived damaged. Who knows, he or she might be pretty decent about it.