Mike, salt air is the least of the issue in my opinion. Yes, galvanic corrosion from three different metals, brass bushing, stainless screw and washer and pot aluminum windsceen V shaped mount, but what is worse is that with the oem bushing being short the water remains trapped in the voids under the washer. Even worse than that is if you use even the slightest amount of grease, the Loctite does not work if the holes are polluted. The corrosion likely occurred from the aluminum to stainless which easily happens, and the effected area would be directly under gap between the brass bushings end and the washer.
This was the first removal of the windscreen mount since new. So about 14 months of use.
As for the additional plastic washer, the area of concern uses flanged plastic bushing if I recall correctly, so I should be good there.
I'll sort something out to correct this minor concern. Probably order some brass rod and make new bushings in the lathe. Just to many other things going on currently.
I should get a billet center arm and do this all at once. Reliability is a good thing.
PK