Well, In all games XY and after, the game will not allow you to battle, saying you need Kalos Rules (ORAS) or something like that.
In all other cases (I have tested battles with my games), it is best if I give an example.
If I Fight my cousin (He has White 2 and I have White), and he uses White Kyurem, on my screen, It appears to be Regular Kyurem, and he can't use Freeze Shock, as it will "Fail". It still had Turboblaze, however.
I am pretty sure that is the same for D/P and SS (which I can test later if you wish), Giratina will look like a regular one, but still have Levitate. Idk if it gets Griseous orb boost, but I can test that, too.
Source: Experience
Hope I helped!