Fortin 102 is the second of two varieties of the 1838-O Dime identified by Seated Liberty Dime guru, Gerry Fortin. He also included a die state of Fortin 101, which is now collected as a sub-variety. Fortin 102 is the so-called "Normal Mintmark" variety, in contrast with Fortin 101 (the "Repunched Mintmark." Fortin 102 is also known as the "Huge O" variety, but without an attribution photo the difference between the Normal and the Huge mintmarks is not immediately clear. Besides, the overpunching on Fortin 101 is evident even on circulated pieces, so, in our opinion, that is the easier tool for differentiating between these two varieties.
Fortin 102 is barely scarce, certainly more common than the Fortin 101.
Deciding which Fortin 102's are the best is challenging because the Fortin numbering system has not come into widespread use unitl recently, thus there are many unattributed 1838-O Dimes out in the market. After having examining quite a few images and auction apearances, it looks to us as though MS64 is the best possible grade... and that is a very good grade for an 1838-O Dime. There are several different MS64 Fortin 102's, some of which have great color and eye appeal.