When you give a pet a dagger it looks as if he has 2, thats some graphical bug verant has. If you watch the damage output youll notice "pierce" and "slash", so he is actually using a sword/dagger. If you give him 2 daggers he will pierce/pierce. Nothing will affect the damage he does except for his level. The level 49 pet can hit for 44, 46, 48, 50, or 52, depending on which level you summon.
Gotta love those quad 52s and a kick =)
Maelael
54th Enchanter
Saryrn