The front derailleur looks like a Simplex LJ A200, it might be stronger than the other Simplex front derailleurs you guys are talking about.
Yes, most likely the original went bust long ago, I think this is a suitable replacement.
The rear mech concerns me, the severely oxidized plastic just screams to me- danger.
My guess '73. Most of the '74's that passed through the shop while I was working way back had the Dubois lugs.
The bikes that arrived in '75 returned to Nervex and before '76 had revised graphics.
Almost bought one as a training bike and at that time the club I rode for was sponsored by Peugeot.