hmmm...
i got an Arceus on my Platinum from the GTS at lvl.100 that had all of that in its summary...
and just so you don't freak cause others have, my friend let me borrow his so i could add it to my pokedex and i gave it back!
no hacks!
so also, if it is able to be offered or shows up in the GTS, doesn't that mean it's legit?