I haven't bought a set since WC took over ST, so things may have changed. The rear track lock ghost rings used to be mounted to the receiver by screws in holes you tapped. I've never had one come of an 870 (at least no one has complained) likewise the front sight could be glued onto the pedestal and then a screw put into a hole you tapped in the pedestal. At that point it's adhesion is dependent on the soldering job which originally set the pedetal in place at the factory. Generally, in my experience, the pedestal barrels are thinner walled than the police bead barrels.