Guys, I'm actually fairly certain it's real. Why?
I did a screen capture and did a ratio of measurements based on the one thing that has to be a constant; the SIM sleeve cover. Granted I may have been one or two pixels off, my math tells me that a 6s sim door is 0.115 of the phone's height. The screengrab, best estimate, is 0.134 of the total height. That would indicate the video has a phone of 86% of the height total over the 6s. The ACTUAL difference between a 6s and 5s in measured height is that the 5s is 89.5% of the height of a 6s.
So count me in on this being probably true. That said, I don't guarantee my measurements or my math.