I've got a 67- when they still had a little more intricate lug-
I've had it since 1987- and I DID pay $100 for it then!

Anyway- consider the tapped dropout lucky too- now you can put a modern Campy or shimano derailleur on it- and they sometimes really need replacing after 40 years- the Simplex were plastic- they worked well- the back much better than the front-
I replaced that years ago- but just put a campy Nuovo Record on a few months back after the original went bonkers- wasn't about to pay more for an original simplex- and besides i put an Ofmega Super Record Knock off crank on too. I,ve got the MX bars and stem because my tired old back can't take the drops anymore- after racing 14 seasons when I was young.

yeah, your 531 decal is in a different place- mine disintegrated but was under the Oxydol sticker- I would have more scoffed at it back in the day- and road a Colnago and an Exxon Graftek and a Masi- and a Paramount track bike- but I think the old Peugeot has a certain grace and elegance- and the scuptured lugs went out at the turn of the '70'on most bikes. The old frame just keeps rolling even if I have too much weight on it now-

I've got a Daccordi frame in a corner oof the bedroom in case it ever cracks-