Check your barrel lug for a date of manufacture and initials, you could call TC and see if there are records on it. As far as how legal it would be, that's a matter of state laws. If you can't budge the brake then, I don't think I'd worry about getting it off. You can't make a removable brake to be non-removable unless you send it to a custom barrel shop and then, they may not be able to help you. This all hinges on how demanding the game warden is in your area anyway.
If there's no way that the barrel is un-threading, then it may already be silver soldered, what then?