Looks like FS-501/RPM-001. Not identical, but is it close enough given the amount of circulation? http://varietyvista.com/06 Mercury Dime/RPMs 1941S.htm http://images.pcgs.com/CoinFacts/13240636_1279903_max.jpg Picked up $1 face in merc dimes for an artist that works with existing silver objects.
Not all RPMs are listed. This appears to be a new discovery if you ask me. Does not match up to RPM-001 enough for me to call it so, but definitely an RPM.
