Just an FYI post here about Greenfield's candy and their postcard issues...
They also produced a set of postcards of New York Scenes that have been cataloged as E263 (image found on non-sports side)...
http://www1.coe.neu.edu/~dan/Etype/j263.html
Thus, a case could be made that the Rose cards could be E263-2 or E-Uncataloged. I'm not making that claim but there is precedent for them to be an E-card if the "New York Scenes" set was eventually added (not sure when they were first cataloged as E263). There are several non-sport postcard sets included in the ACC in the gum/candy section (E230, E257, E263, E265, etc.)
-Rhett