http://www.americanwarlibrary.com/vietnam/vwc10.htm
Lyndon Johnson took measures to assure they would not.
"Of the 7262 blacks who died, 6, 955 or 96% were Army and Marine enlisted men. The combination of our selective service policies, our AFQT testing of both drafted and volunteers, the need for skilled enlisted men in many areas of the armed forces, all conspired to assign blacks in greater numbers to the combat units of the Army and Marine Corps. Early in the war, when blacks made up about 11.0% of our V'nam force, black casualties soared to over 20% of the total (1965, 1966). Black leaders protested and Pres Johnson ordered that black participation should be cut back in the combat units. As a result, the black casualty rate was cut to 11.5% by 1969."