I've looked at the roofline of the cab in the video, froze the picture and went to my garage to look at the rooflines of my Mercedes SL and my Porsche Cab. I have to say that the rooflines on the cab don't look at all like the roofline of the current  Porsche cab. It slopes down at a steeper angle, very much like the Mercedes SL folding hardtop.

It will be interesting to see if they have managed to find the room to stow away a folding hardtop.