Ship assist modules provide a per-ship bonus.  The only restriction is that you need to have a weapon to receive an attack assist or a defense to receive a defense assist.  It doesn't matter what kind of weapon or defense.

For example, my transport with no weapons or defenses gets no assist at all.  But if I have a fighter with 1 beam attack and 1 shield defense, it will receive any and all available assists, be they beam,  missile, armor, shield, whatever.  A fighter with only 1 beam attack and no defenses would receive all the attack assist, but no defense assist, and vice-versa.