The token is listed as S-GM-285. (Link: http://www.ngccoin.com/certlookup/index.aspx?CertNumber=3391750-023) I have never heard of this system before. I know the Pollock Number on the piece is P-5391 (Link: http://www.ngccoin.com/NGCCoinExplorer/CoinDetail.aspx?CoinID=49019) Can anyone enlighten me?
I have a reference book on Franklin Medals which uses that numbering system, or at least one that I assume is the same. The book is "The Medals of Franklin" by Phil W. Greenslet. The id number given is just GM-285. This token is cupro-nickel clad, and has an R-6 rarity (16-30 known). In case you could not read the small print on the obverse, it says AUG. C. FRANK CO. To delve further into the numbering system, I suspect the letter "G" represents Greenslet's name. He uses two numbering systems in his book, "GM" is used for Franklin medal identification, and "GT" is used for Franklin token identification. Regarding the leading "S-" of what seems to be the id number, I am going to take a guess that it stands for David Schenkman, who edited the book, and provided Greenslet with, in Phil's words, invaluable dedication and guidance in producing this work. Perhaps Schenkman came up with the idea for the numbering system. NGC adds a letter for the originator of at least one other numbering system of which I am aware. NGC adds the letter "F" to identification numbers shown on their Civil War token slabs, presumably representing Fuld's name, although I have never seen a Civil War Token id number ever include the letter "F" aside from its use on slabs. I do not consider the "F" to be part of the id number for cwts, and I likewise would not consider the "S" to be part of the id number for your medal, but merely a designator of the identification system being used.
That is amazing research! It does sound like a very obscure system. When I asked NGC about it they actually said to send the coin back for reholdering under the Pollock System.
With exonumia, it is not uncommon for multiple identification systems to exist for a given series. If you ever look at Rulau's U.S. token book, you will often find 2, 3, 4, maybe more additional id references for a token in addition to the one that he lists it under. While some of these systems may seem obscure, whichever system is the most recent is likely the best system to use, as newer systems tend to be expanded beyond the listings in prior systems. If you do send it back, I would suggest they include both id numbers on the label.