I have a 580+ Mini-14 5.56 Tactical 16 in with threaded muzzle.

I've read the shoulder after the threads is tapered, not squared, so a suppressor or suppressor adapter won't mount concentrically and would lead to a baffle strike.

Is this true? I haven't removed the factory flash suppressor on mine because it's on there pretty tight.

Is this mounting issue a possibility or definite?

Would a gunsmith have to remove the barrel to square the mounting shoulder?