Blue Book Pocket Guide for Colt Dates of Manufacture R.L. Wilson Edited By John R. Allen GS41569 US$ 19.95 Pref. Cust. Discount 5% By R.L. Wilson. The only publication containing all available Colt serialization between 1836-1998! Simply a must for any Colt shooter, collector, dealer, or enthusiast. 4 X 5, softcover, 124pp.