Not necessary. According to the theory, at least one of the holes in the skull was under 6mm in diameter. Also, some of the xrays shows a cloud of radiopaque material in the brain supposedly being the result of a 5.6mm frangible projectile.  That's the reason why the brain was replaced, which I think is factual.  Pathology experts said that the brain which was supposed to be  Kennedy's looked liked it had been fixed in formalin for days.  Also, although there was massive tissue loss, it weighed more than the average male brain.  I'm not saying I agree with the premise, but some aspects are likely factual.