The MS Production one I got has a kind of cup situation at the bottom that fits around the swingarm; absolute PITA to get on therefore immovable when fitted, even without fixings.
The MS ones don't need anything, they chain guide secures them to the top of the swing arm, and the bottom clips under the swingarm, it's a b*tch to get on and off (remove rearset etc) and once on it isn't going anywhere