If dialga and palkia have spacial rend and roar of time, would giratina's be outrage/draco meteor?
Giratina's signature move is Shadow Force, a Ghost-type move. Outrage and Draco Meteor are not signature moves since there are many other Pokemon that can learn them.
More information on signature moves here.
No, it can learn many dragon-type moves, but it's signature move is a ghost-type move(Shadow Force). Dialga and Palkia's signature moves are Roar of Time and Spacial Rend. They are both Dragon type moves. Not Giratina.