The thing is the back of the card looks exactly the same as any other card there is no off centering of any kind on the back just on the frontLooks like a miscut card which seems to happen fairly frequently in English sets. The border of a Houndoom Ex is what is shown on the right side of the M Mewtwo card.
Since the card was probably printed on the back and on the front separately, I would consider it normal that the back is in the correct position. The biggest indicator to me that this card is not fake is that the holosheet is shining the same as an official one should. =)The thing is the back of the card looks exactly the same as any other card there is no off centering of any kind on the back just on the front