No way I'd let someone demand the price of a new pair! I'll say it's for a living history presentation and the asking price ought to be little more than cost of shipping.
By the way, Kersey is a weave, not a color. It has a noticeable double wale texture. The official Army name for the color was sky blue. It was originally supposed to be made of a dark blue warp and a white weft which appeared at a distance to be a light blue, but in practice this was almost never done; instead, the material was dyed in lots. Generally, the lighter shades were made into trousers, darker ones went to make overcoats (greatcoats), and of course the dark blue was for fatigue blouses. *whack!* Ow... My Lovely Bride just smacked me and got me out of Lecture Mode... thanks, Honey... I think...