Having been there in the rough, I can tell you it is entirely authentic. Really great footage, too.
I have to say I was most mesmerized, though, by the guide, Hawke...and, after Googling him, see he is the real deal. I hope to see more of him on Discovery.
My son and I were so impressed with Myke Hawk and felt that he makes Survivorman look like a wimp. He and Les should do a "survive-off." Unfortunately, this kind of contest can only be decided by ending in the death of one of them! I put my money on Myke!