That wouldn't any great surprise in itself since you start off with something familiar and then redesign the overall appearance as you go along for the "new look" that will become tue finished product. It's just like the Vista themes are a newer look to those first seen with XP in that sense.
When looking at a site like youtube where anyone can upload just about anything that raises all the doubts there fast there however not knowing just who posts what. On one posting with two videos about Vista someone simply pointed a camcorder at the screen and moved around clicking on everything in a Vista stinks posting.
The video was simply too lame to be credible. Just like the one supposedly being Windows 7 you are still looking at amateur hour there.
You're not seeing any of this from credible sources.