I have an NGC graded Oregon state quarter. The label says it is 'SMS'. Is this another way of saying it is a satin finish coin?
Yes NGC calls the coins for the 2005 to 2010 mint sets SMS. In my opinion a foolish move because there was nothing "special" about these sets. ALL of the mint sets from 2005 to 2010 were satin finish. They weren't "special" they were normal. And it was expected at the time that the satin finish was going to be the normal finish from then on.
As @Conder101 stated and you guessed it's just the specification that NGC decided to give to mint sets from those years that the mint labeled as having a satin finish. Why they chose SMS and not simply Satin or something when the SMS 65-67 coins also get that labeling and look very very different is beyond me.