Ron Guth:
As in 1879, production of Dimes took place only at the Philadelphia Mint. Again, the mintage was small, but it was considerably larger than the previous year (36,000 versus 14,000). Despite the larger mintage, the 1880 Dime is actually harder to find in Mint State than the 1879. Even so, the PCGS CoinFacts Condition Census starts at a whoppping MS67 and tops out with a single PCGS MS68.
Researcher Gerry Fortin has identified only three die pairs for this date, only two of which were used for circulation strikes. Because one of the Proof die pairs was later used on regular issue coins, it is not uncommon to find Prooflike examples that can easily be confused for a Proof.