Identify vintage bicycle brand I don't know much about bicycles but I came across one that I want to offer to my nephew since he is into vintage race bikes. I would like to know the original brand of the bicycle/frame since I want to replicate it with the right decals. I was told the frame tubes are Reynolds 531 and from the equipment (Mafac, Simplex, Belleri) I assume the bicycle is probably French from the 70s after several searches enter image description here. Thank you in advance for your help.
Not particularly fine lugwork. Look like Prugnat lugs, but not S4s. Fork crown isn't too finely filed either. Can't tell the brand of ends from the shots. Straight brake bridge with no tangs at the stays. Can't see BB very well at all. Nor chainstay bridge. Is Campag brazeon cable guides? Can't see. Are forks replacements? Does the fork raking look like it's cheaply done? Match the quality of the lugwork? Fork ends match the stay ends? What else could narrow down its country of origin?