Nintendo's definition of what constitutes a legit Mew is law. Definitions are not opinions, they are facts. Certificates of Authenticity were given to trainers who received Mew at the Toys'R'Us distribution events. Nintendo defines a fraudulent Mew as any Mew that was/is not paired with a CoA...
I'm sorry. Your intentions are beautiful, they truly are. You want to give others a legitimate Mew through a copy of your game save file that you selflessly backed up and have generously given to this community! I commend you for your efforts! I truly do.
However. At the end of the day...