You have Merles and Six States.
If they are using a greasable centering flange the standard pin yoke for them has just a small tin shield compared to the rubber boot on non greaseable flange. Keeping the ball greased is the standard defense against contamination.
Ok, interesting. It is Greaseable with a needle zerk. They suggest doing this at each tire rotation or oil change, which always take place at 5000 miles for me.
