Since these were offered with a full money back guarantee by the seller I took a chance and purchased a handful of them being there was no risk.
Once received I reached out to another board member who had more knowledge than I in this area who confirmed they were in fact not period. Oddly enough though they did have some age to them and were not recently produced. Not 19th century, but probably were created in the 50's or 60's as a novelty. The mounts were quite old and were brittle and musty and the images themselves were on an older photographic type of paper, but re-shot in a larger format from the smaller cabinets which can be found if you Google search.
The seller has already kept his word and refunded all money due. All is good!
ps - Thanks Brian...