If there were originally two styles of a part, MB will sometimes discontinue the old style and have only the new style available for purchase if it fits the cars that originally had the old style without trouble. Other parts such as oil caps and winshield washer fluid motors are the same way.

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.