There in neoseeker there´s a lot of fake codes for WWF Attitude like the No Blocking Mode or Be Vince McMahon.

Do you know if those codes really work?

Yeah, those cheats are fake... I personally completed the N64 version of this game using The Rock in the Career Mode w/ the difficulty setting on hard just a few days ago. You get nothing more than the usual cheats you get if you win every title/special event using ANYONE in the game, nothing changes.

Euro: Sable, Marc Mero, Trainer selectable, New Creations Options, Squeaky Mode

Intercontinental: Jaqueline and Chyna selectable as wrestlers, Extra Attribute Points, Big Head Mode
Heavyweight: Beep Mode, Ego Mode, Head selectable as wrestler

King of the Ring PPV
Kurrgan and Taka Michinoku selectable as wrestlers

Summer Slam PPV
Sgt. Slaughter and Shawn Michaels selectable as wrestlers

Royal Rumble PPV
Jerry Lawler and Paul Bearer selectable as wrestlers

those are ALL of the WWF Attitude cheats you will ever find, unless you use a game shark or some shit, sorry man... it's bullshit =/