December 1875 Special Printing 2nd Printing's "Broken C"

In May of 2006 the U.S. Philatelic Classics Society published in The Chronicle, the conformation of a Constant Overprint Variety of the Official Stamps Specimen second Special Printing. During the December 2nd Special printing of sold out Agriculture, Executive, Justice, and State Department stamps the letter C of the overprint broke at the top.
I have a copy of the 2014 Scott Specialized that does not have a catalog number for them. Have these four stamps been assigned a number or designation?
The Second printing received the lower-case b to designate the second printing, thus becoming O1Sb, O10Sb, O25Sb, and O57Sb. The Small Dotted i's then became O1Sb c, O10Sb c, O25Sb c, and O57Sb c.
If I follow the above pattern would the below be O1Sb d, O10Sb d, O25Sb d, and O57Sb d?

The small "dotted i" is listed, but not any of the others. That and "sepcimen" are the only listings.