I'm not an anchor expert, but I believe the ball on the stock is simply a counter-weight to keep the bent part pointing downward. I could be wrong, but I think I remember reading that somewhere, will try to relocate that this evening.
As for conservation, I would use electrolytic reduction to stabilize the iron, probably 7 or 8 months should do it. There are formulas to help you decide how long, or we can help you here, just ask. I would do it with the encrustation on, just out of habit. On this anchor it wouldn't hurt much to hammer it off ahead of time, but I always like to let things cook for a bit before I remove any encrustation. After the conservation is complete, paint it with some epoxy based paint or some type of sealer to keep it looking nice, then inspect it yearly and make sure it stays sealed.