The catch-up freestyle "the real freestyle"?

I've never seen (underwater video) a catch-up stroke used in freestyle in any meet. I've seen more of a mirror stroke pattern than catch-up. I've been told that during the 800 meter free, Ian Thorpe used a modified catch up but when I look at frame by frame I don't see it. I'm confused when I look at the webstie below that tells me that the catch-up stroke is the way freestyle should be done. Tell me what you think. Coach T. windnseaswim.com/catchup2.html