Hey, Hugh
I had to look up shiv in a slang dictionary. If you've seen pictures of me, do I look like I'd have carried a shiv back in 1972? Let me rephrase that...Seriously, I don't know what Muir is like now (though since I left someone decided to make what was the front of the school on Lincoln Ave. the BACK of the school for some reason).
I don't know how old you are or if you lived in that area back then, but the there was no gang violence (cuz' there were no gangs -- and we thought gangs meant singing and choreographed dancing like in West Side Story), no campus security checkpoints, metal detectors, drug-sniffing dogs, electronic gates or anything else back in those days. We had great teachers AND parents who really cared about our education. Needless to say, if no one carried knives they certainly wouldn't even dream of carrying firearms. David Lee Roth was (nominally!) a student at Muir. Some fuzzy-brained, drug-addled friends claim that he sat in with one of my crappy bands back then, but I don't remember that!
While I was there Muir switched athletic leagues from Foothill to Pacific (or vice versa). Film producer Ron Howard, who back then was just known as Opie from the Andy Griffiths show, went to Burroughs HS and some of us saw him when we went there for a track meet.
More specific to your question, this was largely an age of innocence among the students. Muir was the most racially integrated of the schools; we were probably feared (if that's even the proper word) to some degree because that's just how things are. If kids' minds aren't poisoned by their parents on socio-political issues, they are much more open to the world. Having said that, we ALL thought Compton, Centennial, Crenshaw, Lincloln, et al. were the rowdy schools and we were deathly afraid of them!