Keihin peened/staked the backs of the screws so they won't vibrate out. Anyways there's an X pressed in the threaded bit sticking out the back side of the actuating shaft. You can file the protruding screw (the staked part) off with the butterfly open if you're careful, then the screws come out pretty easy. I can't think of a way to re-stake new screws that's not a real PITA, so I have used small fastener loctite. None have worked loose yet. I like to polish the plates to a mirror finish and use round head SS allen screws to reattach them. I don't think it makes any measurable difference to the airflow, but they look nice.