EBay, Collectors, Flea Market & Antiques

I have seen photos with embossing, like the raised lettering of a notary, and I took those to be prints by the original photo studio. A photographer might issue a batch of a photo he took for an event, and distribute them to participants, for example. I believe this was a common practice from about 1900 to the 1950s. Don't know if it faded out, or when.

If you can get a good closeup of the embossing, you might query a couple prominent auction houses to see if there's any interest. They must get questions like that every month.