If this all started from a dumb wrestling match, I doubt a gun or knife was ever needed. Were the two of you alone? Probably not, I imagine it was some young hothead trying to show off in front of friends. Even if you had one, if he'd managed to pin you how would a gun or knife have helped? You'd have had to know ahead of time that he would be too serious. And even if you drew a knife or gun, having seen how badly this kid handled a friendly match, who's to say he wouldn't handle a weapon being drawn on him even worse.
Still, if you just absolutely wanted a knife in this situation I'd say a fixed blade is the only way to go. If this kid was truly set on choking you out, and already had you pinned, you wouldn't want to fumble with a folder.