There is no No Head, only chest, hands, legs and feet. The "No"-set boosts your SEXY stat, which is useful for Fucko, because he's got a weapon that boosts his CRITS based on his SEXY stat. It's a pistol called "Heartache", and you can randomly get it from Icutalus's chest (the boss of the first floor of the Water Dungeon). You can just savescum in front of the chest until you get it. Equip the entire "No"-set, also give Fucko the Pin Of Acceptance you get for completing the pink dragon's questline, and another accessoir and a headpiece that give lots of SEXY. Then, during battle, use Fucko's skill "Fan The Hammer", that special move consists of 5 attacks, that now have a higher chance to crit, and also deal additional crit damage based on your SEXY stat. The damage potential with that build is unreal!
Yes, you can get the set on the 3rd floor. The walkthrough also has a section for ingame items, if you're looking for anything specific.