No they're not. The Saints Tornado and Vulture are helicopters used in the Heli Assualt activitys and the last mission were you destroy the Deadlious.
The SideShooter or Oppressor as it is known in the game is used for Guardian Angel activity and mission like were you take control of the boat,heli and the Luchadores car.
And the Morning Star Vulture is in the mission were the Saints are having a party and all the Ho's rebel against them.
These are not Add-on but special vehicles.