Somewhat of a mystery here as to the origin of these stills. Google searches give one and only one result for these two actors working together and that is Episode 15, Season 6 of "The Virginian" entitled "The Fortress" broadcast on Dec. 27, 1967 on NBC. The only thing is that the illustration of Nielsen looks nothing like the character he played in that episode. These are obviously by the same artist and they were together when I acquired them so there clearly is something in common. Given the lack of other work together, I have to think that the most likely answer is that these in fact do date from the TV show cited, the older-looking Leslie Nielsen notwithstanding.
Authentic original prints on photo paper and definitely not any kind of aftermarket or anything. They have some light wrinkles to them but mostly around the corners. The Sara Lane has a small tear on left edge at top middle. Cutting an inlay mat to mask these minor blemishes would be a simple task, if anyone cares to frame them.
There is nothing marked or written on the back so I cannot say who the artist is except the Sara Lane in particular makes me think Mort Drucker. But it could have been a lot of people most of whom I would never have known. Definitely scarce renditions, don't expect to see them again too soon if ever.