I have considerable respect for both tw and RevDocDrew but note they have very divergent opinions about this. I have no compunctions about opening chokes on guns I intend to use so they suit my needs. I dislike fiddling with screw in chokes so that I wouldn't do. So my Parker 20ga has been opened from Mod/Full to a very functional skeet and modified (which did very well in S. Dakota on pheasants and always on desert quail in AZ.) I also opened the chokes the same on a Sempert Kreighoff sidelock 16ga. The old Kreighoff wasn't marked as to choke originally so a collector would have no way of knowing it had been opened except my word.
