1) Just send the bolt back to them...
2) Or run it, see how it runs.
3) Buy another bolt.
4) You could blend the radius and small step, done in a few minutes.
Them take the bolt apart and take .001" or .002" max, off the bolt face increasing the head space by that amount.
It'd still most likely be in print, but one should gauge it first to make sure.
5) Or a combination of the above.
lots of choices ...take your pick.