[thecatspajamas]

I would suggest not focusing on the studio mount (i.e. card) itself except to compare it to the one on the second link I posted and ask yourself why 2 different studios' mounts would have the same photo affixed. That in itself would make me very very suspicious. Original studio mounts from the period are relatively easy to find, and both the one your uncle has and the one in the second link I posted are likely genuine MOUNTS. The photograph affixed to them is another story. Having only relatively low-quality scans to view in both cases, I would hazard a guess that one, or more likely both, of the photographs themselves are not genuine.

Easiest thing to do first is to look at the photo under magnification and see if the image is composed of lots of little dots (printed image) or is an actual photograph. Beyond that, someone like Scott or David or Rhys who has dealt with more cabinet mounts than I have should be able to tell you what to look for.

I could certainly be wrong, but I don't have a good feeling about this one.