All gold plated hardware wears - tuners get touched a lot, and it's most the acidity of the person's skin that determines the type of wear. Some just stay smooth and wear down to the base metal. Some get pitted and bumpy and gross. The gold plating itself doesn't tarnish, but since sweat travels down to underplated layers (nickel and copper) through small pores, they can oxidize and you can't really clean under the gold plating.
We gave up on our position on gold tuners long ago. You'll notice the oldest Alembics almost exclusively have chrome tuners. This is because the chrome plating wears much better. But sooooooo many people complained the chrome didn't match the gold so we eventually just put the gold tuners on, I think sometime in the 1990s.
29 years is kind of a long time. Do players really expect something that old, and that's hopefully been played a whole bunch, to still look new? Tuners are pretty cheap to replace and you can get another couple decades of use out of them.
I actually think that the gold hardware on this bass (because all the hardware looks goldplated even in the smallish photos) was cleaned with metal polish, which you should never do - it just greatly accelerates the wearing off process. Just clean with a soft cloth. Use a damp cloth if you need to remove gunge, then dry with another soft dry cloth. For the bridge, tailpiece, nut and plates, they would have to be sanded down with micromesh to a flat surface and replated. That part won't be cheap.
Also looks like Brazilian Rosewood burl to me. I don't recall ever having Indian Rosewood in burl.
