And Stevens was not the primary target. The first thing the attackers did was setup road blocks as the Turkish Diplomats were leaving. You normally do not start with roadblocks, since that would tip your hand. My guess is the Turkish Diplomats were one of the primary targets and that is why the roadblocks were setup first.
So yes, it was an attack to remove the covert weapons supply line. Including the Turkish aspect. IMHO.
What was the outcome of the Turkish diplomats? Haven’t heard....