I had my previous B37 for eight years and never had a problem except sometimes a bit of stiffness on the heads outlet so I think that Bavaria have been using suitable valves – from my limited experience.
There was no sign of any corrosion including on the handles which I think are just steel. On my previous boat – which was 18 years old when I sold her the handles were starting to rust somewhat.

The only place I saw any corrosion on Goodeau was around the handle for the sail drive water inlet.