The PX-10 just may be the most common bike from that era asked about on this forum. They sold a bunch of them back then. Including one to me in 72.
Nice to see a blue one.
FWIW, Gus Salmon just did a run of French Reynolds 531 water slide decals, which he showed off over on the CR list. They look very nice. When I last looked, though, the only comment was from some member saying he had neglected to add the little accents over the "e's' in "reinforces, etc.
Know Gus, I'll bet he fixes that, and then he may have the only truly accurate early French language 531 decals available.