The issue with the "new" posts is that they are very bright white and just doesnt look nice. New ones on the right in the pic. Some of us lucked out and tapped into a stock of NOS off white posts (left side in pic). Im down to my last 100.
So as long as surface of the posts havnt deteriorated (white spotting etc) then they'll clean up. I keep a stash of old ones should I need a couple for a machine that needs it.
You can usually clean up anything. washers I buy new stainless from HomeDepot. acorns are a pain.