There are many, many differences. I can only think of a few off the top of my head, and these reflect my experience in a small rural high school in Pennsylvania.
Teachers could bully and threaten the students. I had one history teacher that had been at my school forever. You could tell he hated his job and didn’t care much for students. He’d called us a bunch of young “jabonies” and threatened that we’d catch the back of his hand if we didn’t shut up in class. After I graduated, I found out that jaboney meant “hoodlum” or “loser”.
Teachers and students both had smoking areas on campus. Smoking in the bathrooms was common, as was students using chewing tobacco and spitting into containers during class.
** Between classes at an ’80s high school
Teachers seemed to have a much more lax attitude regarding alcohol use than they do today. In one of my chemistry classes, we made pure ethyl alcohol. We knew in advance we’d be doing this, so we brought those small cartons of orange juice to class with us and enjoyed screwdrivers while we learned about chemistry. The teacher knew and never mentioned it.
Almost all of the boys brought a pocket knife to school, and no one thought anything of it. We saw them as tools, not weapons. I never saw or heard of anyone being threatened with a knife.
It was common for students to bully other students, and no one did anything about it. I saw kids take horrible abuse.
There were no police in schools; it just wasn’t a thing.
** In the school parking lot
We had one computer that was accessible to students. It was in the physics classroom and was used mostly for kids to play computer football. This didn’t have any graphics, just lines of text that told you what happened after you chose a play.
Corporal punishment was common. We all knew that part of the punishment for getting really out of line was going to be a couple of whacks.
We could wear pretty much whatever we wanted to school as long as it didn’t have any profanities on it.