The 503 blade in the OT is a perfect example of Bob W's description of the last (month?) at the Schrade factory. BTW, Delrin is a molded plastic which was "sawcut" in the OTs and "ivory" smooth in the "scrimshaw" models, but it was all Delrin plastic. There were a very few knives made with micarta, the most notable being the American Express boxed set of Presidents Jackson, Lincoln, Washington and Jefferson. There were quite a few loose knives at the end with "blank" "ivory" smooth handles which had not yet received the hot scrimshaw process.