The chairs are very light as totally made of aluminum, flexing the sheet to carry out back and sitting with ergonomic hints.
There are no screws but only rivets to annex the plans to the supporting structure.
I am a product of pure industrial taste that originally constituted the furniture of a medical office in Rome and reminiscent of the production realized for the Montecatini offices from Gio Ponti during the aurkey imposed by the fascist regime in Italy.
Light wear due to age and use, Patina due to age and use, The chairs are stable and in good condition, one has a small cut on the sheet metal visible in the photos you have available.