Yeah you're right hydreigon but there's something little i can add.
If you choose Giratina spot (so you get Giratina) you will get a level 1 Giratina With item Griseous Orb.
If you choose the spot where you get Dialga you will get a level 1 Dialga holding item Adamant Orb.
Same with Palkia, If you choose the spot where you get Palkia you will get a level 1 Palkia holding item Lustrous Orb.
But as hydreigon said, Giratina, Palkia and Dialga will be in standard red and white pokeball.