Iconic,
Yes, this is our old discussion on the colour of the sill trims. We had this specific page with colours and matrials on the forum before, speaking about 280SL from 012089 onwards. I was suspecting there may be a later update, but it does not seem so.
It does say "dark blue", but I do not think this is the only truth. I think it could have been that the colour was changed to black or dark grey later during production and I would fully understand if Daimler decided not to produce another lot of dark blue trims, but used what they had on stock. They might or might have not documented it via a memo or update of some sort. It could have been different for Europe and US - there are hundreds of possibilities. This was the time of printed materials, updates were not that easy.
I have dark blue rubber trims on the sills, but it may not be correct, I know that.
I quoted several times on this forum an elder gentleman I met in Essen years ago, who used to work for Daimler in the 60-ies. And he said just that: for trim, upholstery, etc., if an item was out of stock, they just used what they had, sometimes asking ordering party if it is ok, if the difference was substantial. My question at that time was about square weave carpet on my 1970 car.