In the early/mid 00s the yamaha sleds used an electronic servo to operate the pv.... this isn't as hard as your thinking. I mean fuck, if you are wasting the breath to put actual thought into PVs on a bangshee you might as well waste the energy to do something to control them.
You can see the groove in the shaft, I'd replace it. As for the cover, I can't tell if that is corrosion from some brackish water, or leftover remnants of someone's attempt to remove a gasket with a 20 grit wheel. Regardless, I'd replace it as well.