No. It is fake [although there is an Action Replay code to get it, but when you go in the battle screen it will appear as Deoxys or Jirachi (50/50 Chance)].
It depends on the person. Jirachi is in Hoenn. Which means Emerald,Ruby,Sapphire,Etc. Same with Deoxys. I like Jirachi more personally. But hey, it's you opinion.
It is said that if you breed deoxys and ditto you will get a random egg.I am working on it right now, but it is taking a long time...if you breed deoxys and jirachi you get jixoryI've been trying to...