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Fascinating!
But I won't be bidding. Even assuming they would really hold full pressure on the rim, what would you use them for?
Back in the day, you would use them for a race when you thought you might get a good result. That did involve getting to the finish without puncturing.
I notice that these tyres do not appear to be silks, and they are not even a pair. Also, they are not said to be 1970, but '1970s', which may include the period when they were not reliable - quite possibly the reason they've never been used.
There's a NOS 1970 pair of the fabled Doudoigne Grand Prix des Nations on ebay France. Still in their original wrapping. Opening bid is 750 euro. https://www.ebay.fr/itm/176136352426?mkcid=16&mkevt=1&mkrid=709-127639-2357-0&ssspo=qPhR6hUaSpe&sssrc=2047675&ssuid=0PDdBtKRSKe&widget_ver=artemis&media=COPY