[prewarsports]

In general...

Get the photo wet in a small spot and as it dries if the "gloss" gets sticky to the touch then you have a gelatin photo which means that it is at least somewhat old. It at least helps eliminate the photo from being of modern production. If you tilt it to the light and the black portions of the photo have a super shiny (silvery look) that will also help determine its age as well. Otherwise its almost impossible unless you have it in hand for evaluation.

Sam West Photo looks like a restrike (from a copy negative) made later by a collector seeking autographs.