I had a gunsmith tell me on some brands it can depend gun to gun due to tolerances. Said worse case scenario an adjustable choke could be installed. I'm kind of in the same dilemma as you, I hate to buy a gun that can't be threaded. I have leaned more toward looking at the modified and full choked barrels thinking there would be more material to work with than a more open choked barrel. I'm usually wrong though, just ask my wife lol. Good luck and keep us posted on what you find out or do.