Well it's good to know I'm not crazy!
Turns out though, I ordered the wrong flash hider. I got the one for the older (and thinner) Mini-14 barrels. For some reason he still installed it, very poorly, and sent me out the door.
This is a good gun shop he's working for, so I'm willing to give them a chance to make it right. But the lack of communication is chipping away at their rep.