No it's not.
Do it with a disc at incredibly slow speed with your hand starting already way past the right pec almost at it's full extension position. initiate the pivot and clamp down as the you feel the weight shift of the disc - you can throw surprisingly far like this.
Find this feeling and reinforce it.
Add more and more motion but keep the feeling at each introduction of more motion.
in time the feeling of gripping at the hit becomes part of your drive and you can feel if you haven't achieved it before the discs flight shows you you haven't.
Blake T's hammer drills can work this feeling to an extent as well although don't quite get the full hit feeling down as this is a secondary extension after the first.
You can really work on it by just dangling the disc from your fingertips up until the lower arm chop is shooting out at which point you have to grip down hard to prevent the disc just flopping out of your hand. (Can anyone remember the big gun that drives like this, I'm sure Chris Voight used to but I can't find any video showing it. )
My point is that when the form is done correctly, a conscious thought of "gripping" a disc doesn't come into play. I'm still confused on the 3 and 4 oclock thing.