Bob,
They were made from scraps of materials found elsewhere in the cars, so this is no surprise. There were at least two "levels" of kits for Mercedes of the era -- one had the snaps and the other had a piece of cloth that tied around it. The SLs got the former.
So was the royal blue kit the type that tied? If so, I suspect it was originally from a W 114.
Douglas Kim
New York
USA