Are you saying he threaded the muzzle and when you received it back it had marks from the jaws of the lath because he didn't sleeve it....or it slipped in his barrel vice because he took it out of the action and marred it at the receiver?
it looks like from the schematic of the tube fed and mag fed versions it uses a takedown screw to remove the barrel...but I don't have it in my hand either. It is sad that it wasn't sleeved by the person that did it.
We caused a cosmetic flaw in my new one. I think the only way you can tell is that it is more polished in that area. If I decide to Cerakote it or just bead blast it to take away the sheen I don't think you will see it. He used a file while the barrel turned in the lath then finished it up with 800 & 1K grit emery cloth