Here is a complete 400 card Stereoview set by Keystone View Co. While the cards themselves are not dated, some of the descriptions on the backs contain dates with the most current being 1924 and a few in 1923. I believe most of the images were taken much earlier than those dates. While the outer box covers display some exterior wear, they and the inner boxes are fully intact.
Additionally the cards are near pristine with excellent photo images showing little or no wear and the cards themselves appear hardly used.