yes. Look at his swipes in the beginning of the video, for example the one between 4 and 5 seconds. He makes a BIG swipe to turn about 45 degrees on-screen.
Then, look at the moment he aimlocks, 43-44 seconds. Just before he aimlocks, he moves his hand slightly off the left side of the mouse. It looks like he presses something, maybe mouse4 or a numpad key that hey was fiddling with earlier. But in any case, at the moment of the aimlock, his hand movement is a FRACTION of what his earlier swipe was.