Interesting observation, UTW. I've never seen any early footage of Don singing Silver Dagger. I guess I just assumed he did, but it's quite possible that they hadn't fully developed the amazing 4-part (and later 5) harmonies that they would come to be so well known for at that point. When I get a chance, I'll have to try to listen real closely to see how many voices I can hear. Oh my - the work never ends!