I can't see the pictures either but IIRC there is something called zinc lice or something like that. Without seeing the pictures, it's hard to tell.
Doesn't really matter anyway. If the main body is used up its time to buy a Proform main body and be done with it. There is no zinc in those if that is the issue you are having.
It's simply bolt your parts onto that main body and go. Plus you will have changeable main and idle air bleeds and while its apart you can drill and tap it for T slot restricters and really clean up the tune up.
