Yes, many times...in 1968, 1969, 1970, 1977, 1980, 1981, 1985, 1994, 1998, 1999, 2000, 2001, 2003, 2004, 2009 and 2011.
According to pro-football-reference.com, the Redskins have swept the Cowboys 5 times - 1984, 1987, 1995, 2005, 2012.
Yes. The Cowboys have swept the home-and-away series with Washington 16 times, most recently during the 2011 season.
Yes. In Jimmy Johnson's first season as head coach (1989), the Cowboys went 1-15. Their only victory was over the Washington Redskins in Week 9.
There is no record of anyone by that name ever playing for the Cowboys; the 2008 official Dallas Cowboys media guide does not include him on the all-time roster.
THE DALLAS COWBOYS
The Dallas Cowboys
The obvious choice is Emmitt Smith, who played for the Dallas Cowboys from 1990 to 2002. He is the all-time rushing leader in the history of the National Football League with 18,355 yards, and the Cowboys' career record holder with 17,162. He also won four league rushing titles (in 1991, 1992, 1993 and 1995), and was both a league Most Valuable Player (in 1993) and a Super Bowl MVP (for Super Bowl XXVIII).