I think you will find there is no problem in practice with the components of the wind vane. It seems to me that vanes do not last long anyway. Birds are a major problem. I make my own out of fibreglass or carbon fibre, resin stainless steel shaft but if I get a few seasons I ma lucky.
Any ss bolts into Al can be helped with Duralac or grease of any sort to minimise corrosion. olewill
