commissioned officer in this  movie has a CIB (Combat Infantryman Badge) on their uniform. CIBs  are awarded to Infantry or Special Forces soldiers who have served  in combat. All of the officers in the movie are branched Armor  (according to the insignia on their uniforms) and it can be assumed  that the enlisted soldiers have Armor or related MOSs (military  occupational specialty, Army term for job). I doubt every officer  and NCO character was previously branched Infantry or SF and served  in combat before switching to Armor.