False.
Here is Article 15 of NCAA Rule 9:
ARTICLE 15. Horse Collar Tackle
All players are prohibited from grabbing the inside back collar of the shoulder pads
or jersey, or the inside collar of the side of the shoulder pads
or jersey, and immediately pulling the ball carrier down. This does not apply to a ball carrier, including a potential forward passer, who is inside the tackle box (Rule 2-34). Note that the tackle box disintegrates when the ball leaves it.
It was a horse collar tackle. No doubt about it.