13th Infantry Regiment Unit Crest (First At Vicksburg) pair

13th Infantry Regiment Unit Crest (First At Vicksburg) pair. United States Army 13th Infantry Regiment Unit Crest (First At Vicksburg) These distinctive unit insignia (DUI) were worn by the 13th Infantry Regiment. Their motto is First At Vicksburg. This DUI was originally approved for the 13th Infantry Regiment in 1923. Unit crests are worn on the Army Class A Service Green and Army Service Uniform (ASU). I believe the 31 on the back represents the 31st regiment.