By 1864 a color-bearer held the rank of 1st Lieutenant and Ensign, and therefore must be regularly enrolled. Except in very unusual cases, civilian volunteers would never be in the army. Only regularly enrolled Confederate soldiers would be allowed to carry the regimental flag.

CHAP. LXXVI.--An Act creating the office of Ensign in the army of the Confederate States.

The Congress of the Confederate States of America do enact, That there shall be appointed by the President, to each regiment of infantry in the army of the Confederate States an officer to be known as ensign, with the rank, pay and allowances of a first lieutenant, whose duty it shall be to bear the colors of the regiment, but without right to command in the field.

APPROVED February 17, 1864.

Statutes at Large of the Confederate States of America,
Passed at the Fourth Session of the First Congress; 1863-4.

More about Confederate ensigns --
http://michaelchardy.blogspot.com/2009/07/ensign-v-color-guard.html
http://www.cowanauctions.com/auctions/item.aspx?ItemId=35449

S/b a record of a man among 19th Alabama service files nominated by the regimental commander as 1st Lieutenant and Ensign. It was his duty to compose a letter describing the qualifications of his nominee. The War Department then issued a commission. The other ensigns in Deas Brigade are known; just not one for the 19th Alabama (yet).