Antique Photograph Military Cadet JJ Klain San Francisco Cabinet Card Photo

This is an antique cabinet card photo of what appears to me to be a military cadet. The back of the card is stamped JJ Klain Photographer 921 McAllister St San Francisco. This is interesting because pioneer Western photographer Nathaniel Klain worked at that address from 1881 - the first mention of a JJ Klain was in 1886 and Nathaniels last mention in a San Francisco directory was in 1888. Its difficult to know whether JJ and Nathaniel were related or even the same person. The card measures 4 1/4 by 6 1/2. The photo is yellowed, definitely showing its age, and there is a missing corner at the bottom right, but the image is intact. Ive tried to show the badge cap in close-up, which may provide some tip as to where this young man was a cadet. Nice early San Francisco photo!