Valca, have a look at tge back of the cranks. There will be a number in either a circle or diamond. Circle is 1980s diamond is 1970s.
Then have a look at the pat number on top of the rear derrailleur, next to the cable entry. Hopefully the two numbers match. Like a 7 or 8 in the diamond of the cranks and 77 or 78 in rear derailleur. My guess is that this is a complete bicycle and not made up from parts but it is a little later than you thought. Probably 77 or 78 hopefully you can confirm as per above. It is stunningly beautiful bike, and a few years ago woujd ve worth over $5000, but the market is pretty depressed right now. Good luck with the sale.
Then have a look at the pat number on top of the rear derrailleur, next to the cable entry. Hopefully the two numbers match. Like a 7 or 8 in the diamond of the cranks and 77 or 78 in rear derailleur. My guess is that this is a complete bicycle and not made up from parts but it is a little later than you thought. Probably 77 or 78 hopefully you can confirm as per above. It is stunningly beautiful bike, and a few years ago woujd ve worth over $5000, but the market is pretty depressed right now. Good luck with the sale.