Please forgive my noob question. I'm fairly new to guns and extremely new to shotguns. I just got my first one yesterday in a trade. It's a remington 870 express magnum. I did not know what a choke was till today but now that I do I'd like to find out what kind my gun has. Is there any way to tell by just looking at it? I don't have a tool to remove it? Any help would be much appreciated. Thanks.