Photo of "Gabriel" is actually Hubbard D. Pryor
Well, Ladies and Gentlemen. I found him, so here are the particulars:
Photograph of Hubbard D. Pryor before enlisting. Carte de visite by A. S. Morse (life dates unknown) of Nashville, Tennessee, March or April 1864. Collections of National Archives and Records Administration, Washington, D.C.
Engraving based on the carte de visite of Pryor before enlistment, printed in the July 2, 1864, issue of Harper's Weekly. Collection of the author.
Photograph of Pvt. Hubbard D. Pryor, Company A, Forty-fourth U.S. Colored Infantry. Carte de visite by A. S. Morse (life dates unknown) of Nashville, Tennessee, March or April 1864. Collections of National Archives and Records Administration, Washington, D.C.
Engraving showing an idealized image of Pryor in uniform, printed in the July 2, 1864, issue of Harper's Weekly. Collection of the author.
Photograph of Hubbard D. Pryor before enlisting. Carte de visite by A. S. Morse (life dates unknown) of Nashville, Tennessee, March or April 1864. Collections of National Archives and Records Administration, Washington, D.C.
Engraving based on the carte de visite of Pryor before enlistment, printed in the July 2, 1864, issue of Harper's Weekly. Collection of the author.
Photograph of Pvt. Hubbard D. Pryor, Company A, Forty-fourth U.S. Colored Infantry. Carte de visite by A. S. Morse (life dates unknown) of Nashville, Tennessee, March or April 1864. Collections of National Archives and Records Administration, Washington, D.C.
Engraving showing an idealized image of Pryor in uniform, printed in the July 2, 1864, issue of Harper's Weekly. Collection of the author.