How do I prove if this an authentic Ib Kofod Larsen armchair?  

Hello.
I have this Ib Kofod Larsen attributed easy chair.
Please find the model of chair on design resource Decopedia here:
http://www.deconet.com/decopedia/template/seating/chaises-lounge/Easy-chair-by-Ib-Kofod-Larsen-id-114172
Absolutely identical.
However, no makers stamp. A stamp however would be problematic, as if it ever had one it would have likely appeared on the base of the seat. But the floral upholstery I acquired it in was almost certainly a later edition - very 1980s - with new backing cloth where an original label might have been.
So what I have to go on:
The age of the wood is old - you can tell from the way it has shaded over the years, darkened near the joints, the depth of the grain.
The age of the stuffing: old, 40s/50s, natural straw/hay. Post 1950s it would more likely be foam.
Pencil numbering and marks by the maker inside the frame.
The place it was sourced: reputable Copenhagen antiques dealer
The figure/shape of the wood - the shape of the arms, where it joins to the legs seems unmistakably Ib Kofod Larsen. I've had some different model Kofod larsen armchairs before - genuine, but not stamped, and they have had this signature design as the arm meets the legs - thin, curved and elegant.
What do you guys think? I'm in no doubt as to its authenticity - but any way of proving it?
http://www.osimodern.com/shop/featured-home-page/featured/ib-kofod-larsen-easy-chair-denmark-1950s
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