Check the Japanese shops/auction sites.. Brooklyn Machine Works was resurected from the dead by (i think) W-Base Japan back in 2020/21ish.. you're not going to find everything you want but the market isn't as strong over there so it's a lot cheaper.. everytime i used to buy something from JP, i used to tag a few sets of BMW bar caps into my order.. i got some black ano ones too.
Compared to my origins from 20yrs previous
They were retailing for 7500¥ (£40).. vintage were selling on ebay for £220 so i stuck the new sets on ebay for £95 and doubled my money.. I even sold a set to Indonisia