There's not a lot of demand for the original enV so I don't think anyone went through the trouble of producing a fake one. However, if the sticker on the inside doesn't look right, then it may be a refurbished model.
If you have service with a particular service provider, then they will likely unlock it for you if you tell them you want to use it while you travel overseas. They would do this because you are a customer and they want to help you. If you do not have service with that particular provider, then...