I'd say that he has some information correct and some "incorrect," for some of the physiology. A lot of people have mistaken the wrist action that drives the stick and fingers to be actually being the fingers that are driving the sticks (look at the interior hand shot around the 8:00 min mark). That's not to say that the finger (tympani) method isn't valid or that Gordy's method isn't valid either. I just think that these methods start to run into a bit of trouble when they show these "uncontrolled" rebounds.
Just to bring up Buddy Rich quickly, he always stated that his technique was wrist driven and not from the fingers. However you'll see plenty of experts showing you Buddy's finger technique.
His fingers were passive in comparison to what Gordy is demonstrating at the 8:15 mark (and also I don't like how high the stick is when he demonstrates the "close").
I've taken a lot of technique lessons from a lot of people and by far the best technique I've learned was from Jack Verga. Jack is is "the" guy.
He was a student of Murray Spivak and then D i c k Wilson... actually he was a long time friend with D. Wilson and thus I think the most qualified to teach "the" method.
Here you can see some basic techniques from the style in the video link below.
I would recommend looking for a teacher that has studied with Spivak, or better yet, with Wilson for a number of years. This is a subtle technique and it takes some time and effort to make it so ... effortless!
Jack sells a technique book based on the system called "The Essential Rudiments of Drumming In The Natural and Logical Order Of Succession as taught by Murray Spivack and Richard Wilson" and can be had via this link: https://itunes.apple.com/us/book/ess...613552663?ls=1
I'll provide a couple of links to show more of the Spivak/Wilson techniques, but do so reluctantly because they don't really give you a chance to get some feedback and clear up any questions on the grip, let alone the wrist movements.