There should have been no reason for him to rebraze the barrel lug back to the barrel.

He would have had to completely remove all of the blueing and bead blast the barrel and then repolish it if that was the desired finish. This can sometimes make the brazing line look larger than it looked before.

Honestly it is hard to say with out actually seeingthe barrel.

Why not just ask him what he did and if it is something that you have questions about ask him why he had to do it.