To be honest, I'm not sure. One of the game creators said that there will be NO third version for the game. However, I heard that many people used gaming codes to find out that there was a stone called the "God Stone" which is Gray in color. I have a theory, though. Since the right side of Kyurem's body is basically damaged with a shorter wing and horn, in the third version, those part will be UNDAMAGED and Kyurem will show it's true form. What do you think?

Note: I've asked this question on yahoo answers before

link:link

I've heard about Pokemon grey but that's all I'm really shore about but it could be a posibility but outher than that I really don't know........

Perhaps it isn't planned for now Pkmn Grey...I hope so!
Now is tradition, the third version! Can be caught both Reshiram & Zekrom?

Perhaps,I think that there's a chance because it would probably be like Emerald with Rayquaza and Platinum with Giratina,so basically I think there's a good chance,and I would really like to third version of it,I think it would be really cool.

maybe ... i think there will be a third version :D