If you get a fake, you can return it for a real one. They'll pay the return shipping (or in some cases they'll just let you keep the fake and send you a real one).
That said, the Acekard 2 or Edge are both much better flash carts. I like the Acekard 2 the best, and it's only a few dollars more than the DSTT you're looking at.
-Bri