I don't see anything wrong from the pictures. Not sure what the notched tab is for, but I think it does spin, kind'a sort'a, not so important that it spins, but it must move freely in and out. You should be able to push it in and see the balls on the bottom, the ones falling down by gravity, push up the ramps to the center of the ball cage, then fall back to the lower edge when released. You can trial fit the cover back on and feel this same action by moving the lever back and forth.
I remember something about a drain/vent hole up inside the cam where the cup stem goes in... But yours appears to have flats machined on the side of the stem. Yours may have both. Those are there to keep oil or air from being trapped and influencing the governor. Be sure the hole is clear if it has one.