Depends on the school, but I would not do it. Most schools have a zero tolerance policy which includes fake weapons. I read a year or two back about an elementary school child that was suspended because he used his hand like a gun.
No way about ayear ago a kid built a clock in dallas tx the teacher thought it was a bomb. It played on the news and the cops let him go after two days in jail. We live in a era of paranoi
I wouldn't do that if I were you.
Now in today's wave of hysterical paranoia.
No. It's not ok. Paper or not, it's a sign of violence.