Bertoia Diamond Chair 421 - Real or fake  

Hi addicts,

I bought my dream chair last week - a Bertoia Diamond Chair. But the seller didn't have any papers on it, so I just need a confirmation, that its not a fake. Not knowing has been killing me.

It has a Knoll 'Made in Italy' sticker on the frame - suppose that a good thing. Edges seem to be sleek and nicely finished. Only thing putting my off is the grinding on the frame (last foto) - I don't know if it is normal or from a previous reperation.

Info: paid 475 euro for the chair.

I hope you guys can help me out!
<img class="wpforoimg" src=" http://d1t1u890k7d3ys.cloudfront.net/cdn/farfuture/2Lg0TIoigkZq5MZOW8u5GZ