panton stacking chair  

the ones here in America ...
the ones here in America say Herman miller on them

cheers LRF , i keep reading...
cheers LRF , i keep reading about fins or no fins, do you know if they should have fins underneath or not ?

This is a rather simple one...
After a lot of trials and errors in painted solid foam (BASF)and other "new" plastics, the original chairs were made in glass fiber reenforced polyester. Vitra re-edited them in a re-enforced Polypropylene. The original is glossy and heavier, the re-edition has a textured surface is injection moulded and is substantially lighter. If you are familiar with the way polyester is finished (re-polished at the edges) versus a parting line from an injection moulded piece, that is a very safe indication to.
Someone lucky enough to own one might fill you in on the markings, but I suspect that because of the technology the original is not as detailed as the injection moulded one.

The fins....
are clearly a feature of the injected moulded ones, in other words of the recent re-productions

These can have problems
I've read time and time again that these panton chair have the habit of cracking at the stress point.
My guess is that the newer models have fixed that problem.....hopefully

I have one original Panton ...
I have one original Panton fiberglass/plastic chair from the 70 s and it is like heavy glass and has the Herman Miller stamp , i paid 50 bucks at a estate sale for that one ,
I bought 4 on line for around the swimming pool in white and they were really nice, they came from Alphaville, I drilled a hole so the water would drain out as i had heard you do not want that old water sitting on the seat, I have to admit for a reproduction it is pretty good and nice and heavy, and for a chair around the pool it is perfect, they also make a indoor one for double the price that they say is great, like who really cares about the out door chairs, Who ever molded these did a good job,

thanks guys for the info,...
thanks guys for the info, i'm off to see them this week, i shall let you know what i find.

The current
The current vitra productions have no fins underneath - just a smooth contour. They are also marked Vitra and bear Panton's signature.