I have entered a profile for Benoni S. Wheeler, who served in the Union Army during the civil war, apparently at least in part as a commander of colored infantry; his grave marker has BENONI S. WHEELER, CAPTAIN, US CLD TROOPS CAPT CIVIL WAR.
There are pension records for him on FamilySearch.
Someone who knows more than me about the army in the Civil War and the records of the military for those who served in the union army may want to look at his profile, and complete his service units, add the appropriate stickers, etc..