Did the Veteran need to serve in combat to qualify?
No, the only requirement is that the veteran served at least one day during time of war, as part of a minimum 90 day deployment that was for other than training purposes. The critical dates are:
World War II- 12/7/1941 to 12/31/1946
Korean conflict- 6/27/1950 to 12/31/1955
Vietnam War- 8/5/1964 to 5/7/1975