mrfatboy and Alfred,
Here are some comments that I hope help you out:
I've sold one and still have one, both are 1970 280 SLs that were both built in August of 1969.
Vins: 012160 and 012287.
Both have 3 point static Kangol belts with Kangol tags dated 1969 and words in English (Kangol is an English company you probably know that).
Both are US delivered cars.
Both have a dash (-) in the "43" box on their respective data cards.
On the 012160 car the metal piece bolted to the B pillar used to hang down naturally.
On the 012287 car the metal piece bolted to the B pillar stays up for some reason, and this position makes more sense to me so that the belt approaches the seat from a higher point so the belt doesn’t have to go up and over the seat.
I have the plastic part that holds the metal U shaped chrome end of the belt that is shown on thelews car, but I have never been satisfied on how it fits and functions. John’s, thelews’, car shows the metal piece rotated down and the plastic piece looks nice on there, but when I have mine in that position, and I pull the belt taught, the plastic part has a tendency to fall off. When it is rotated up, it looks funny to me, but does not fall off. I believe Alfred stated that it should be "up" from the Mercedes documentation. So, it doesn't look right to me, but works that way !!
Very interesting topic ! Thanks.
Mark