I have read conflicting posts about the front brake calipers from a 91 300CE (also used on the E320, etc). Are they 4 piston or just 2 piston?

I plan on buying new rotors, 300CE calipers (if they are 4 piston), along with sourcing some 500E rear brakes. From what I gather, this should all be a bolt on affair?

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1991 300E - 212K and rising fast...