mine doesnt appear to be threaded. Does this sound right?
My 18" 870 doesn't have a vented rib and the front bead was not threaded. I just had the local gunsmith replace it with a fiber optic front bead.
yes, quite possibly. The Wingmasters were threaded and the Express models were pressed. I don't know if that still holds true.
If it is pressed into a vent rib, they seem to come out fairly easy. If it is pressed into a pedestal, the most common fix is to cut it off and drill and tap for a threaded sight.