.../...Also had a closer look at the existing fabric that is wrapped around all the bows. I would love to know if this is factory material
IMHO, the fabric of choice to install for a Pagoda soft top is the "Sonnenland" type. See description of this in the Wiki. Inside colour cremé
Mercedes do not weave/produce their own soft top fabric, they have vendors (for the cabriolet cars being produced today).
As for our old SL types, M-B Classic buys the products they offer to customers, sewn most likely by some external vendor.
So anyway, in my view when one buys a W113 soft top, one should ensure that the vendor uses bona fide "Sonnenland" material, of the correct type. Note, there is Sonnenland fabric on sale which is indeed high quality but not at all suited for our use; instead these fit like modern cabriolets with motorized soft top mechanism etc.
On this webpage if you scroll down a bit some facts can be found:
http://www.cabrio.de/khm/en/softtop-materials/Hans in Sweden
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