In 1868, production of Dimes at the Philadelphia Mint reached 464,000 coins, the largest mintage since 1862. In fact, this mintage was larger than the combined mintages of the previous five years. Despite this increased availability, Mint State 1868 Dimes remain elusive. A small number of MS64 examples exist, but Gems in MS65 and better are very difficult to find.
According to Gerry Fortin, an expert on Seated Liberty Dimes, twelve die pairs were used to strike 1868 Dimes. Two of those die pairs were first used to strike Proof coins, then later used to strike coins for circulation. This created lots of confusion as to what is a Proof and what is a circulation strike because the two versions often look very similar. Even Gene Gardner, another person who knew a lot about Seated Liberty coins, was not sure about his own 1868 Dime (he eventually went with the NGC grade of MS65*).