Glad to hear you were able to get it running again and it shoots.
That's one reason I don't mess with customers pre-fits. I can't give them any guarantee beyond it will stay on the action when I screw it on. Better to spend a few more bucks and have a guarantee from me. Any error's don't make it out of my shop as with most reputable guys.
On the flip side of that, I am always curious to look at others work when it comes through my doors. I had a similar issue a few years back where I bought a rifle for myself where I was 98% sure who built the rifle. When I took it apart the threads were not cut correctly and there was excessive slop in the threads. To account for that the person that installed the barrel added Red Loctite. What I later found out was that the rifle was built by the guy I thought, but it had been re-barreled by someone else. I know who that someone else was and this didn't surprise me. I still have it and it's one of my personal rifles. It is safe enough to shoot and actually shoots OK despite the horror show going on with the threads. When I get time, I'll set it back and do it right. I rarely have time for my own stuff though.. LOL...
I've had a handful of rifles from builders such as S&S precision, and the late Stan Ware to name a few, and they never disappoint. Work is as I would expect. I've also had a few from a couple well know guys, that will remain unnamed, that were disappointing to say the least.