Ethancol - not true in all cases. Lightning claws, powerfists and similar *require* 2 of the *same* in order to get the bonus attack.
So it is irrelevant that a stormbolter isnt a
CCW, as powerfists need another powerfist to get that extra attack - and in addition pistols, which DO count as a
CCW, are Assault 1 weapons now
IT sounds like you have some 4th ed hangovers, bust that book out and have a read