Paul,
Question, I don't ever gamble. But as I understand Vegas basically puts (and moves) the spread to have an equal number of $ on both sides and wins with the vig. If so, I would assume that Dallas as America's team must be bet to win pushing the "real spread" away from the final score and to cover both sides. As such do you know if Dallas usually doesn't cover? If I were to gamble I would look for trends like that instead of who I think is actually going to cover.
Not sure if you know, only ask because you mentioned the spread moving.