This sounds like the war stories people tell to entertain their grandkids.
Please someone of the period tell if the CIA would ever had included a man of Kerrys rank and duties in a covert gun running operation.
People who are supposed to know about such things have said that Kerry's claims are preposterous.
First off, an inexperienced junior officer such as Kerry would never have been asked to undertake such a sensitive mission.
Second, Swift boats were anything but stealthy -- very loud diesels and relatively deep draft. Insertion missions would have used something much smaller...and much, much quieter. Indeed, the CIA had a fleet of such boats for that specific purpose.
Kerry's tales are nothing more than an exercise in lily gilding, told by a fool.