not all, but MOST are. so hances are, he is telling the truth.
BUT, i still wouldn't pick it up from him--- you will need to run a 4-wire o2 for most vtec motor's computer, and the CX harness is wired for a single wire.
it will not be a plug N play swap -- which is what you're looking to do so it seems. the EX/si harness is still the easiest to work with.
and more so, if your car isn't a 92-- you will still need to run the wires from the ecu up to the cannon plugs on the shock tower.
and wait-- ecu harness?? you mean the ecu to the shock tower part right?
yeah, that will have the vtec wires on it... but it won't have the 4-wire o2 lines... so you will need to run the heated sensor wire (the other 2 are grounds)