First, i lived in what was to become silicon valley (western San Jose, walking distance to Cupertino, not more than 5 miles from Zilog, where Apple started, etc.), not the Australian outback. I built things with that surplus uA741's at age 14 and i was born in 1951, thus 1965 was when it happened. Checking the first availability dates shows 1964 or earlier for 741's locally to me at the time. Check around with other old timers that were in the area at that time on the availability.