A premature look at the potential 53 for the Cowboys. The Dallas Cowboys have wrapped up the open practices in Oxnard and are headed to the Rocky Mountains for some joint work with the Denver Broncos before playing them in their first preseason game. We have been watching the reports out of training camp for every shred of information about the team they will field. Preseason games and the practices, mostly closed, from here on will add more information that could well shuffle things. But based on the data so far, here is an early attempt at a roster projection.…