Roger, roger SS. ... don't think they would plate bronze with SS.
I know three boats with nice SS pins. As I remember Bill's boat has a set of nice SS pins ... with stainless locking pins as well.
I'm thinking the only thing bronze that moves, other than parts of the motor ... is the prop.

I'm thinking that somewhere we decided that the easiest way to fabricate new pintles was to cut a piece of 1" prop shaft and use a pin and washer on top and just the pin on the bottom.