I looked it up on Bricklink, and these pieces don't come in any shade of brown or gold.
At this point I wonder if we're dealing with a resin molding experiment. If you can make Kanohi that way, why not other pieces as well?
Well, I downloaded it, and put it into Blender. I was able to color and pose it, except that the "elbow poles" seem to be stuck. When I try to rotate them, the icosahedron moves, but the corresponding limb of the model does not.