Any idea how to identify and obtain this part?

I have an 825i with the glass windshield. It is held onto the roll cage with four clamps. They appear to be the standard clamps used on many of the parts to clamp onto the rollbars. For the windshield clamps only, they have a white rubber buffer behind the clamp. I think it is there to maintain tension and prevent rattling. Unfortunately, they are only held in via friction and I managed to loose one.

I stopped by my local dealer and they were unable to locate the missing part. We found the clamp but it does not show the white rubber piece.

Any idea on a part number or a description that I can use to locate one?

Here are some pics of the piece.

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