wether or not Frank Hopkins was lying or if this story actually took place is irrelavant. There are millions of stories in america as well as on arabia soil, that state that these races actually took place, and may even today, however, contrary to the so called "scholars" these races are hightly confidential and are kept pretty quiet.
As far as Frank Hopkins winning such a race do you really think it would be to the Arabs best interest to talk about being beaten by an american cowboy and his mustang, let alone have any documentation on such an event, that would go against there beloved royal standards. So the question I believe is inside your self. You can believe that this man and great horse really did these things or you can believe the so called "scholars and skeptics" who by the way make me want to vomit because they always find a way to ruin a perfectly good thing. In the words of poison, "Give me something to beleive in". and then leave it the hell alone.