Found this ref. at the Kansas City Public Library:

During a Jennison raid in Jackson County and Independence, Jennison's right hand man Joseph P. Swain "was immediately taken with a pile of red-dyed sheepskins that occupied one of the cobbler's shelves, which Duke [Joseph P. Duke] used as a decorative topping for the high boots he made. Jennison's men immediately appropriated the red sheepskins, and fashioned them into pairs of leggings. (from, North and South, May 2002, "Better Off In Hell": The Evolution of the Kansas Red Legs by Matthews and Lindberg)