Barry is quite correct. The mounts of each of these cabinets are badly trimmed. They are each undersized for 1870's cabinets and possess border skewing and corner sharpness that can be explained only by trimming. Here is the link that shows the Philadephia cabinets in the Spalding Collection at the New York Public Library.
http://digitalgallery.nypl.org/nypld...word=athletics. If you click on a particular cabinet, it will show a blowup. And if you click the image of the verso, it will show the studio (the same as that which produced the Heritage images). Clicking on "Image Details" will give particulars such as the dimensions. Each cabinet is materially larger than those in Heritage, is cropped much differently by not having the photo go to the edge of the mount, does not exhibit uneven toning, and has round corners (which were how they were issued -- no untrimmed 19th cabinets have corners such as those in Heritage).
Almost certainly the Heritage cabinets were at one time mounted under an overlay for the purpose of making a composite of the team (a typical 19th century procedure). That explains both the trimming and the toning. Albumen photos when originally issued were much less toned than how they appear many years later. The toning is caused by exposure and is irreversible. The portion of each photo that was protected by the overlay and therefore had less exposure is significantly lighter in toning. Here is a link to another lot in the current Heritage sale.
http://sports.ha.com/common/view_ite...8&Lot_No=80002. This Cdv was once part of a composite of the 1872 Boston Red Stockings and too was covered by an overlay for many years. I know the person who first acquired it and removed the overlay. Each underlying Cdv was badly trimmed and showed comparable toning to the Philadelphia cabinets.