If I am not mistaken, "adding" this little detail, however incorrect, is a trademark of Mark Passarelli--at least that's what I've been told.
Mike Webster's restored 230SL has this little detail.
And as for the photo, prior to the Geneva show, there were some shots taken that show up in Engelen's book. My friend, fluent in German, said that the byline in the photo said something about "so nice you'd like to drive it home, but it's clay."