On 8 August 1863, Lt Col Sinex reported that officers employed two Negroes as servants, and no other Negroes were employed [letter, Sinex to Marvin, 8 Aug 1863]
For more about Edgar Gregory's views about Negroes, see the letter he sent to Benjamin Harris on 20 January 1866. He seems to be remarkably unprejudiced for his time, blaming whites for their mistreatment of blacks, praising blacks, and insisting on legal equality.