Double wired edge on Bertoia side chair  

Hello,
I recently bought a few vintage Bertoia side chairs I was hoping to get some insight on one of them which has an "eames" style double wire around the edge of the chair. Looks exactly like my other authentic Knoll Bertoia side chair except for this.
I read about the original design being double wired like this until Herman Miller sued Knoll because HM held the patent for this. So is this some sort of fake or just a very early version? They certainly look old and weathered.
Any idea? Thanks!