I am not familiar with the exact bolt you are talking about but like Colemj I would have reservations about putting anything on the bolt, if the bolt is connected to zinc.
Most of the stuck SS bolts in aluminium are caused by dissimilar metal corrosion
. This will not occur if the bolt is protected by the zinc.
It's very important to maintain good electrical contact with zinc. The voltages are low and the effect of the zinc is easily blocked.
The products like Tef-gel and Duralac prevent corrosion partially by providing some electrical isolation. The zinc may be directly in contact with the sail drive leg, but the best electrical contact is generally via the bolt.
You risk compromising this connection.