Specimen; they dole out "SP" grades for SMS coins.
PCGS gives them Specimen grades, as coinman states.
NGC labels them as SMS, but gives them an "MS" grade.
Thanks for clarifying the ambiguity in my statement. By "they," I was referring to PCGS. I hope my post wasn't misleading (i.e. NGC and PCGS do use different nomenclatures).
Areas of Interest: Original classic gold coins from the Southern mints (New Orleans, Charlotte, and Dahlonega); Carson City minted Morgan Dollars, early copper; high end, quality U.S. type coinage; proof like and deep mirror prooflike coinage; toners including Peace Dollars and classic gold; and cameo and deep/ultra cameo proof coins from 1936-1942.