As I've stated, I never lay -4.5 or more in pre-season. I will finalize my selections tomorrow, but as of now I am passing on this game. If you combine those two sentences, you could rationalize that I lean toward the favorite, so I don't necessarily disagree with you.
Now normally, any pre-season dog of +4.5 or more is an automatic play for me. However, I also like to play against the defending Super Bowl champion in pre-season, and the Colts have never done well in these games under Dungy, preferring not to show their stuff. Also, although the Cowboys also have a history of pre-season indifference, they may have some mild intersest in knocking off the champs to please the home folks.