[Runscott]

Alan, I've never seen a baseball photograph by Chickering that was NOT the Boston ML team. Meaning that what you have is a tough piece to come across.

Chickering stamps come in many different styles, some with only very slight variations - I have identified four different ones, the one you have being one of the four. To me this is significant, as there were plenty of other Chickering mount stamps, but they were only used for non-sports photos. Some of the variations on the black ones are subtle, but still easy to spot.

If he had used only two mounts (one light and one dark) for sports photos, I might draw the conclusion that for some reason he used special mounts for such photos, but given there are at least four different ones, I think they are simply related to a period when he took such photos - cabinet mount designs were changed often by most photographers and you can sometimes date photos by the mount stampings.

Edited to add: the above isn't taking into consideration the designs on the BACKS of the mounts - those also changed, but I haven't been documenting them.