WTH....

I don't think so, but I graduated HS in 1979.

Exactly, there was no major difference in real levels of knife crime back then , but the perception would have been different.
There certainly wasn't an idea of zero tolerance policies which are just a popular lazy reaction to knee jerk hysteria.
If you had graduated another 20 years earlier there also wouldn't have been a major difference in real levels of knife crime and it would be considered perfectly normal or even expected for a young boy to carry a knife.