Thanks for your help. The dates sound about right. The gun was part of a friend's late father's collection. Since his dad and I were both LEOs during the sixties, he gave me a good price on it.
Actually, the first "wonder nine" was the Walther P-38. It also had an eight round magazine, hammer dropping slide mounted safety and double action first shot. The Walther P-38 was developed and first produced for the German military for WW II.