Bertoia bar stool mount  

They look genuine to me.

Looks Right to Me
The welds are in the right place and the gauge of the wire looks right for that period.
My understanding is that there are very few vintage fakes, as fabrication was expensive to reproduce and therefore not worth "knocking off."
I've always thought that the barstool should feature the same base as every other Bertoia chair - no idea why it looks so different. Great looking stools, though.
If you want to clean them up, skip the 0000 steel wool and just use NOXON polish and a soft rag - it will make old chrome gleam like new with minimal effort. (Apologies to those who worship at the Altar of Patina.)

Thanks so much for the replies!
Great, so they are genuine!
I'll try to clean them as soon as possible 😉
Happy new year!
Laurent

Yes
Looks authentic to me as well.