I know nothing for sure, but I will say that when OEMs go to a shaft company, they tell them their desired specs. These specs would match up with the majority of what users(general public) will do good with. Only a small amount of the general public would do well with a Kuro Kage shaft, in their driver. They are tip stiff, and that is something an OEM would not want to be trying to sell 100's of. So, if your shaft looks like the one in that forum pic, I say it's not an 'upgrade' at all; more than likely made to Cobra specs, which would be to play softer in every flex.
I simply don't believe this statement: Cobra tells me it's a Kuro Kage Black. It's 100% the real deal. The graphics are custom graphics for Cobra but otherwise it is the same as the aftermarket version. Even though the black would fit a few more players, than the silver KK which plays stiffer yet.