I am in the process of replacing the rubber weatherstrip/seals for the convertible top windows on my 67 230 sl. I obtained OE pillar seals as well as seals for the roof rails for each window. The window seals came marked left and right (which had to do with the length of each arm, otherwise they were identical), but the A pillar seals had no such markings and were identical. As they will be inserted as mirror images it would be no problem if they were truly identical which they were, with one exception. Each had a plug in one end. If I put them on as is, one side would have the plug at the bottom of the seal and the other would have the plug at the top. After contemplating this for several hours and without instructions from anywhere I could find, including this site, I came to the conclusion that the plugs are removable and could be put in either end of the seal. I found a narrow wooden dowel I could slip (with some Teflon lubricant) down the seal from the open end and pop out the plug(s). Cool! Now my problem became "why did the Germans put this plug there and what was its purpose?". The conclusion I came to is that the plug goes in the top of the seal and prevents the open center of the seal from becoming a column of water when it rains. Is this correct or did I miss another less obvious conclusion?
And while I'm on this matter, its obvious the seals for the windows need to be cut so the top can be retracted, yet the seals for each side come in one piece with a sharp angle corresponding to the angle between the top of the window and its back side. How best to cut the seals to minimize air flow at speed? My thought is to put them on in one piece on each side and then find a razor sharp knife to cut them at the separations of the rails of the top. Is this right or is :-\there a better way?