Dating Bertoia Large Diamond Chairs  

Hi,

I'm trying to get a sense for how to date Bertoia large diamond chairs and wanted to run the following past the group to see if it rings true.

With the understanding that the thickness of the wire is one way to determine approximate age, I am also thinking that the systems for mounting the rubber shock absorbers are another way to get a rough idea of when they were made.

From various photos, I've noticed three variants that I think reflect early-, mid-, and current-era production.

Early is a single metal bar that connects the two shocks together on each side. (See images of the chrome chair with no cushion.)

Mid-era appears to have the shocks individually mounted. (See image of the black framed chair.)

Current-era appears to have a single bar connecting the two mounts on each side, but the bar is beefier than the early era. (See image of the chair with the purple-ish cushion.)

Does that sound accurate and if so, does anyone have a sense for the spans of these various eras?

Sincerely,

John
<img class="wpforoimg" src=" http://d1t1u890k7d3ys.cloudfront.net/cdn/farfuture/