The majority of these are photos of examples in the US Army Finance Corps Museum. You can see the word "SPECIMEN" punched into some of them . Also intermingled are the very few I have picked up recently. These can be identified because they have a scan of the reverse as well.
These pictures are of examples in the U.S. Army Finance Corps Museum. (I apologize for my poor quality pictures. If you have better examples and would allow me to display them I would gladly do so)