The 1993 WTC bombing was definitely labelled terrorism. I remember it as a bit of a shock, that Americans didn't realize people in the Middle East were really pissed at us about something. Oklahoma City was quickly labelled terrorism, many originally assumed it was Mid-East in origin again and were shocked that it was domestic terrorists. I don't remember the Unabomber incident much, but I do remember there was much attention given to his manifesto.