The proof 1873 Closed 3 is a great rarity. According to the definitive 2005 Winter-Bowers reference on the three dollar series, only four to six proofs are known. This makes the proof issue rarer than the proof-only 1873 Open 3, 1875, and 1876, all of which have at least triple the number of survivors. Only the proof 1855 is rarer (three to five known), and by a slender margin.      

The business strike 1873 Closed 3 is also rare. Winter and Bowers estimate a mintage of just 600 to 900 pieces. Identification of the proofs is possible because proofs and business strikes are struck from different pairs of dies. The date location is slightly to the left on the proof, relative to the commercial strikes. The proof obverse die is slightly convex, which gives the obverse field of the present piece a subtly bulged appearance, as made. Harry W. Bass, Jr. was the first to note that 1873 Closed 3 proofs come with and without a bulged obverse field. This suggests that the obverse die was improperly prepared for coinage.