Above is a scene still from Herman Hack's daughter Dorothy Hack. On the right are George Houston and Al 'Fuzzy' St. John and the film is THE LONE RIDER IN FRONTIER FURY (PRC, 1941). There's lots of faces here, and most we can identify. But there's two unidentifieds, and crops/blowups are shown below.

Here's a link to THE LONE RIDER IN FRONTIER FURY cast listing on the Internet Movie Database (IMDb): http://us.imdb.com/title/tt0033845/fullcredits

Left to right below are Archie Hall Sr. (mustache), a very young Lane Bradford, Herman Hack (beard), and our John Doe #7 (with moustache) and John Doe #8 (with the beard).

Left to right above are Augie Gomez, Frank Ellis (mustache), Lew Morphy, George Houston and Al St. John. Bending over and wearing the 'stache is Budd Buster.