I sent a note to AMG asking this question and received the following response (AMG forwarded it to M-B USA):

Thank you for your recent internet query. It was forwarded to Mercedes-Benz USA for response.

Sportline was a Mercedes-Benz in-house product and did not involve participation by AMG.

If we can be of any further assistance, please feel free to call us at 1-800-FOR-MERCedes (1-800-367-6372).

Sincerely,

Heidi Martin
Consumer Promotions
Mercedes-Benz USA, LLC



Mailtext:
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I have a \'98 C43 AMG and a \'93 190E Limited Edition with Sportline (as well as an \'88 420SEL).

Did AMG have any participation in Sportline? I note that the Sportline logo of decreasing trapezoids appears similar to the AMG logo.

Thank you.

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'98 C43 AMG
'88 420SEL
'93 190E Limited Edition (including factory Sportline package)