I don't know of anyone plating Stainless bolts.
And most platings are by nature electrically conductive.
The Tefgel works great at the thread connection. I believe this is also due to the sealing from electrolytes.
while I can only comment on my Zeeko, the stepped plastic washers and plastic self adhesive strip at mast ends does a lot to keep electrolyte out of the thread area.
plus that is the only areas (stainless bolts into Alloy threads) that I have a Galvanic potential.
My experience with Anodising is that the only version of real value is Hard Anodising, and the colour that comes in is just a few shades of yuk.
The colour versions look cool but not up to the durability I would want.
Anodising is a great pretreatment for powdercoating and our results showed it increased the Salt spray test hours to failure nearly five fold.
My two 2004 Outboards have stood up well but the number of sacrificial anodes and the rate I replace them is very eye opening.
Not me in pic. I'm way better looking imho