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Yes, you and your friend are right in there with the dating.
Cycle licenses are most commonly issued for a term of three years so if a license has an expiry of 1971 it was likely issued in 1968.
Cycle looks like it may be what was termed Motobecane's Nomade or Mirage model in the U.S. market.
Here are two catalogue pages from a domestic French market Motobecane catalogue of 1968. My apologies the images are not larger.
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You mention date codes on parts.
Huret began putting these on their fittings in 1978 so cycle too early for that one.
Doubt there would be a date code on the Weinmann brakes.
One spot there is a chance of finding a date is on the bicycle's Rigida SUPERCHROMIX wheel rims, assuming it still has its original wheelset...
some of these exhibit a two digit date marked inside a small diamond symbol next to the manufacturer's name as here -
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Are you able to read the shop transfer; cannot quite make it out.
Looks like the address is Sahara which suggests bicycle sold by a dealer in Las Vegas before someone brought it to Isla Vista.
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