Commissioned or not?
The two noncommissioned officers seated in this Civil War-era stereograph are corporals, designated by the insignia, called chevrons, on their jacket sleeves. The soldier on the far left appears to be wearing a Confederate commissioned officer’s kepi. Note the Austrian Knot, symbolizing the wearer’s rank, on the top of the chasseur-style kepi; it does not match the rank insignia on his sleeve.
National Archives, Records of the Office of the Chief Signal Officer