Just not true. Look at the other big games on OU's schedule and you'll see that nothing comes close to The Ohio State game. their in state rival is 118, and the Texas game is only 188.
OSU is that much because there will be 20k fans there in Scarlet as opposed to Crimson. OSU was en masse at Texas in 2007, and there were 25k at VT last year. It will be the same in Norman