Charlotte Perriand - Les arcs?  

Just bought two marvelous bar stools, basically made of leather and tubular frame. The owners told me their parents bought them in the 70's. But I don't know where.
I was just wondering if they could be from Charlotte Perriand, for les Arcs ski resort.
It seems that different versions/shapes were produced. But can anybody confirm that these are genuine ones? I only found these:
https://www.1stdibs.com/furniture/seating/stools/charlotte-perriand-stools-les-arcs-1960/id-f_765359/
and these:
http://midmod-design.com/archive/4e85d8a0202b5/Charlotte-Perriand-bar-stools-for-Les-Arcs-1960

I've seen elsewhere that the dining chair are sometimes stamped with a date. Mine aren't, is this a problem about their origin?

Thanks for the answers!
Len