Yes it was the time 4:20 when pot smokers met but not at San Rafael High, or maybe they did, and it's a coincidence, but at Edison High School in Huntington Beach California. 1971, and 1972, deals and smoke were happening behind the Horticulture area and 4:20 was the time. It became a code even then, you would raise 4 finger and then 2. It meant see you at the spot at 4:20. There was a reason for the time, it was when the area would be clear of any supervision and was a free place to smoke. There was a lot of pot grown in the horticulture class, and I remember once when we were all waiting for My Hoyland to leave, he came rushing in the room with a flat full of small pot plants and he wanted to know whose they were. The plants were all too small to have been any of ours! Our stuff was already well over 3 feet to 5 feet high and planted throughout the school grounds. My favorite was just outside the principals office window! 420!!!! It's quite possible that some students transferred to San Raf or from there to Edison and brought the code with them?
But 420 was the code for pot smokers, it defined the place and time!
420 was also a group which became a political party one year. Edison was rumored at that time to be high on the list (Nixons watch dog for drugs in schools) of the most wise spread use of pot and so called drugs in the country. 3 narcs were assigned at this time to our school, they were nick named by the 420's as the "Mod Squad" and were all over 25 years old and looked it! LOL! In a predominately white school 1 of them was black, the 3 wore expensive hippy clothes and spoke like cops. They were led on by 420 stoners and at an election rally a certain candidate sponsored by the 420 group, who also passed out Vote for me on rolling papers, made a speech wanting to legalize weed on campus, (That was the 420's agenda) and then at the end of the speech pointed out the Mod Squad, and identified them as undercover narcs. They left in a hurry and were never seen again. The 420's pulled pranks and were known to smoke openly, trying to find ways to make pot accepted.