Czechoslovakia, Socialist Republic, Matte Proof Set 1968 (2) Ducats of Prague, Kremnitz, Ag mm 40 and 30 g 25,10 and 13,24 rare variety in MATTE PROOF, the identifying mark of the Mint is 16-PR (Parma City), while normally these medals were struck at the Mint identified with the mark 1-AR. Matte Proof