Kim, thanks for taking time to draft this timeline. I will add features of 1968 using my PX-10 (Ser# 200631) as example. Due to several features as well as 3-68 stamping on Prestige (red-label) derailleur, I''m assured it's a 1968. Can anyone add 1967 from personal experience?
1968 - All 531 f&f, Nervex pro lugs incl stamped BB shell w/angles, head lugs, seat-cluster incl seat-stay ends and BB shell blackened (perhaps not cluster and BB in all cases as has been reported?), All incl chrome clear-coated ("varnish" in catalog).
Simplex shifters, Criterium?...Mafac Dural Forge calipers, (no original saddle but) Simplex-badged 26.4 steel post. Riveted metal headbadge.
Stronglight Mod.93 Competition crank, Lyotard Berthet pedals, "Peugeot" in simple Gold block letters on downtube decal. Left rear d/o with tab. I'll also add that this 68 has hardwood plug in steerer and I found a cork shoved down the seat-tube...prob an early form of BB protector.
Jack Romans
Sacramento, California