If it is actually stainless, you don't need to worry - the brass is actually going to be sacrificed, not the frame.
If the frame steel, the brass is slightly more cathodic, but not much. The steel would be sacrificed, but not appreciably.
If the frame is aluminum, it would get sacrificed much more rapidly.
Give it a rubdown with some paste wax, candle wax, bees wax and you're good. These are not friction points where the insulator will wear off.
The screws or bushing also need to be protected.