Others might add more detail, but I believe the scroll engraving changed at some specific years. In 1924, he received an award in London, England for the design of his early 22 Rifle. In 1929, his manufacturing was moved to Cobourg, Ontario. "H. W.Cooey Machine & Arms Company" was sold to Olin Corporation (Winchester) in 1961, and I believe several Model numbers were changed around that time (I stand to be corrected, but I believe that is when the Model 60 became the Model 600).