Threading for a brake is on the muzzle. Fluting is on the sides.....I'm not sure how new guy can be guilty of the loose tennon.
As above, unless you have gauges or wires there's no way to know exactly what you have going on. I would guess the smith unscrewed it and spun up his work and was going to torque it up before indexing the brake when the alarms started barking that this thing is too loose. A lot of Remingtons are sloppier than the broke chick in college but shoot good.
