Eames 'time life' lobby chairs; early Vitra versions or Herman Miller?  

Hi Guys,
I am new on this forum.
I recently purchased two Eames 'time life' Lobby Chairs. They are in very good condition and in nice cognac tan.
There are some elements 'I can not place' which are quite different to Herman Miller versions.
The main differences are:
- The black powder coated frame underneath the pillow has a different shape. The brackets (screwed under the pillow) are L-shaped while the Herman Miller versions have flat shaped brackets.
- The rectangular of the mechanism is much more bigger and the spindle is in a different place.
- The lever (which controls the resistance) is curved and has a plastic shell on top while the Herman Miller versions have a straight lever with a chrome plated knob.
- The alloy (side)frames are chrome plated instead of polished aluminum.
- The backside of the pillow/seat has small air holes while the Herman Miller versions have closed leather or fabric.
- The 'allen bolts' have a EU size instead of US like the Herman Miller ones.
The previous owner told me that the elements of these chairs indicate, that they are early Vitra versions dated between '65 - '69. He also told me that, between these years, Vitra assembled executive and lobby chairs for the EU Market. They used genuine Herman Miller parts.
So I've contacted Vitra AG but they say they never assembled these chairs for Herman Miller and that my chairs are original Herman Miller versions. That's strange because my chairs are not simular at all?
Who can help me and give me the right information about these chairs and can explain the different used parts?
As the new owner I'd like to determine the authenticity of the chairs.
Thanks in advance guys!
Best, Robbie from Utrecht, The Netherlands
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