FORMER MULE COLSTON WEATHERINGTON SIGNS WITH COWBOYS WARRENSBURG, MO (July 23, 2001)   Former Central Missouri State University Mules football star Colston Weatherington is officially a member of the National Football League Dallas Cowboys. Chosen in the seventh round of the NFL draft last spring, Weatherington signed a contract last Friday prior to the start of the Cowboys' training camp at Wichita Falls, Texas. Terms of his contract were not disclosed. Weatherington is one of two rookies among nine defensive ends on the Cowboys' training camp roster. He will wear jersey number 67. The Cowboys' first preseason game is Aug. 4 at Oakland against the Raiders.