I couldn’t find any sources, but if you are going to use cheats, and if you have an emulator version of your game on a computer, you should first check Serebii or Bulbapedia for the event, put the event in the emulator, and if everything on the cheat code Victini matches the Serebii or Bulbapedia one, then you could put it in your real game with the cheat. But, people say that just the fact of you even using a cheat code to get your Pokémon makes your Pokémon illegal.