Cannot find anything online.

Did the 911s ever come from the factory with them or just a dealer install thing?

Click to view attachment

*edit, found a thread on a BMW site that mentions that BBS outsourced many of these wheels to Mahle for a while. ????

outsourced or licensed? hmmm

BBS effort to supply the 'look' of their classic (expensive) three piece
wheel at a more affordable price.
I adapted these later versions from the Audi 200 Turbo Quattro to my VW Westfalia
They were OE on a few BMWs and Audis and maybe others but not 911s as far
as I know.
Often fit aftermarket.