This is a Proof coin type...The U.S. Mint mainly consist of 3 mints Philadelphia, Denver & San Francisco...Thus the U.S. Mint at San Francisco is the one noted here for a Proof type made from Special dies and heavy polished for a mirror proof finish ..Your album appears to have just the circulated P-D Mint Marks & no proofs slots....They do sell albums for the circulated with the Proof type...thanks for asking....Carl