Yes, but don't the terrorists immediately take credit for this stuff? Don't they usually announce with the greatest sense of accomplishment the purpose of the attack and their promise of more to come? They do this with the same eclat that proud and joyous researchers would announce they found the cure for cancer or discovered the unified field theory. That is why I never associated the OKC bombing with the terrorists.
I think that the prime movers behind McVeigh and Nichols were Iraqi terrorists - not the same breed as Al Qaeda. They were working for Saddam and wanted to strike a big, spectacular blow upon America, but weren't interested in claiming credit, as Bin Laden or Al Zawahiri or Zakarwi would certainly do.