I haven't seen this footage before (or a DIVX watermark post 2k3 for that matter), and while it's cool I also think it's a fake (via CGI).  If you look at historical pictures of the construction here, you can see the rooftop in the right foreground isn't a perfect match.  Also, I don't think they had 'sicky-sicky gnar-gnar' timelapse technology in the 1960s that could make it appear to have been built in under 3 days.  And who builds a skyscraper at night anyway?  

If anything, this is probably from some Department of Defense propaganda fear-flick to illustrate what it would look like if American cities were built by future Chinese invaders/investment groups.  Fear the efficiency!!

This fear based pic brought to you by the remake of Red Dawn. WOLVERINES!!!