A RPM on a proof after 1985 is not possible. That year they added the mintmark to the models that the master hub was made from for the proofs. So no more punching mintmarks into the proof dies after 1984.
I do not see notching on the upper serif of the S, so I would strongly suspect MDD.
I do not see notching on the upper serif of the S, so I would strongly suspect MDD.





















