I actually have a pristine, virtually never used Newton keyboard. Perhaps when I have time, I will shoot a photo of that.

Yes, I am rather unhappy with the discoloration of that IIgs keyboard. It came with the SE/30 and that's why I originally bid on the system. But the owner clearly did no take care of it by keeping it out of UV light. I now have a keyboard cover over it, but the damage has been done. It also had some connectivity problems, forcing me to solder the connector contacts.

But despite the discoloration, I am not about to paint it!