For a long time, I figured H-D came out with the oval mirror around '71 since the owners manual for the '70 Electra-Glide shows round mirrors. This page from the '70 accessory catalog, shows the long stem oval's part numbers are from'67. What really surprised me, is the (new for '70), short stem mirror was originally designed to be mounted on the under side of the lever. These are the adjustable (slider), types that can be used for left or right.
In the late '70's, I had a friend that ran his this way to be cool. I don't think he knew that's what H-D had intended.
That's what I dig about this stuff. You can always learn something new.
