Fancy lugs were used through at least '72. Other models used through '75. I've never bought into the 'one year only' theory of plain lugs in '73 or '72 or whenever...
Regardless, unless it have the original RD, handlebars or rims your going to have a hard nailing down the exact date. In reality, it doesn't matter, for the most part PX frames didn't change from the early 60's through '74...531 tubing, long dropouts, mish mash of lugs etc.
But, I'd look closely at the fork bands. If they are German flag colors it may suggest production after a German won something big while riding a Peugeot. National Championship, Olympics in '72 etc...
Last edited by miamijim; 02-17-18 at 07:50 PM.