Seeing as it's Peugeot-week, I suppose it's as good a time as any to post this question to the specialists :
what would have been the real difference between the '79 PX10 and PS(N)10 frames, they seem both to be constructed with 531 frametubes AND forks :

http://home.wanadoo.nl/peugeotshow/

Also, what about value difference?

Thanks!