Turned all previously offending surfaces into metal again (chrome, titanium, aluminium), and guess what? Black.

Please note however that not ALL metallic surfaces render as black, only SOME specific surfaces do. For instance inside the cockpit there's a platform and a centre console that are custom coloured metal, and they render fine. The pedals however should be the exact same material, and they consistently render black.

The rear leg is a bit odd: at first it rendered fine as metal, then I replaced it with a decimated version and it became also black. But other parts that I replaced with decimated versions still render fine, so that replacement itself appears to be unrelated.

Mistery, mistery.....

Erik

edit: I was too quick! the pedals now render metallic green as they should, this time they are NOT black. The legs, cockpit frame and cannon still are black though.