Replace the entire unit with a high quality stainless steel.

The endurance has no stop function, so you might buy several, so you'll not have to repeatedly reorder.

Or purchase and install a high quality brass, or a cheap spin-n-grin.

Can anyone please enlighten me what the HECK that gold-discoloration is?

Might it react with [whichever] future strainers are placed on it?

P.S. I'm not bothering with replacing the whole drain, so forget that angle.

Looks like nobody wants to tackle this with a 10 foot pole, huh?

I mean, for someone's sink to become even more grossly-goldish looking than it is already is a risk worse than even Obamacare!

Should I try the cleaning forum or metalworking forum next?
That's the Q.

You've already gotten multiple answers. You just didn't like them. It's a low quality unit that the plating is wearing off of. Replace it.

Not really sure what your question is or what you're trying to achieve here. As others have said, the plating has worn off. Are you just trying to cover up the discoloration? Then I guess, go with the cheap fix and cover it up with the strainer. To me that would just be a pain to deal with every time I needed to fill the sink with water and drain it, and I would always know that it didn't really solve the real issue. If it were me, and the discoloration bothered me that much I would fix it correctly and replace the whole basket and in the future use cleaners appropriate to the task. It's not expensive or difficult to do.

zud eats the plating off, so you're seeing the brass underneath - thats what the gold stuff is. been there done that.

"You've already gotten multiple answers. You just didn't like them. It's a low quality unit that the plating is wearing off of. Replace it."

If there is an annual award for best response to a post, I nominate this one.

Many (most) sink drain flanges from the 1950s look a bit like this, or at least the ones I've seen do. If yours didn't have the brass exposed before the Zud, then it was perhaps unusual.

As for your question, which I don't think anyone has actually answered, I think you'll be fine sticking whatever strainer basket in there that you want. I've never noticed continuing corrosion on my mother's sink drain, for example, and hers looks pretty much like your original picture. I never noticed a problem from the brass showing in our pre-remodel kitchen either.

It's from the 50s. Don't borrow trouble and try to get the whole flange replaced. Get a strainer you like and enjoy!