I recently changed both discs on my 1990 300SE. They were both OE discs with the Mercedes star embossed in them. The car had only 61k on the clock when I changed them. The rear one was like new, but I changed it anyway. I replaced them with Lemforder discs that were identical to the originals except for the Mercedes star.

Not too long ago I purchased a job lot of '80s and '90s era Mercedes parts in order to acquire some items for my W126. In that lot were 4 discs, all of them for the rear. One was original Mercedes, two were Lemforder and one was Meyle. The discs that were in the Lemforder and Meryle packages were absolutely identical to the original Mercedes disc except both had the Mercedes star and part number ground out of them. That tells me they were manufactured by the same company that manufactures them for Mercedes. Additionally, they all have "Jurid" "SGF" embossed in them also.