My Mk II has the earlier seat back tilt mechanism. There is a cover over the return spring on each side. It is supposed to be shiny. The question is with what? Is it chrome or is it nickel?
If the latter then I can probably re-plate it at home (one of my least favourite jobs!).
I am in the the middle of the slow process of stripping and / or recolouring the interior. The front seats precipitated this in that the leather although original is cracked stained and burned in places, requiring some repair etc. If I just repaired the squabs and backs that were bad I would then have a very odd looking interior. So I am recolouring everything. The veneered door caps had to come off anyway, so it was not too much trouble to take off the door panels too.