Per the 1861 US Army Regulations, Chaplains were authorized to wear a single breasted Officer's frockcoat made in 19 ounce BLACK WOOL and having a black cotton lining. By US Regulations the buttons are covered with black cloth also. According to US Regulations, Chaplains did not wear shoulder boards during this period. In 1864, the Army Uniform Board enhanced the Chaplain's Frockcoat with the addition of "herringbone" braid in black across the chest at the buttons and buttonholes.  Please refer to photo below. Note that the buttons are still black.  This coat was used by Army Chaplains until 1880.