[BillyCoxDodgers3B]

The photos all appear to be of gentlemen from a similar era. Also, it could look like the photos are recessed and the ovals are cut into a mat board.

Above the central photo, the second word strikes me as being "Club", but it's not clear enough to say with certainty. You would think "baseball" to still be spelled as two separate words on a piece from that era, so that first word must be something else.