In that video, the quality off image in the clamshell screen seems to be noticeable bad, kind of like loosly Chroma Keyed. Just an opinion. Sorry about my English.
No problem, I don't know English very well either...
Maybe it's just the screen they used .
That said, if it's a fake, it's very well done. Cause one can clearly see Yosemite running on it, they boot it unplugged to anything apparently. So if it's a fake , it would take a completely modded 10.4 (or 5) to look and run like Yosemite (and I would love to have that), or sending the vid signal to the iBook screen from another i5 Mac wirelessly. Or the vid is edited to show a Yosemite screen, in any case it's very well done...