1992 United States Mint Silver Proof Set. 5 Coins Inside. Black box and COA. United States Proof Set 1992 5 coins. All coins included in the set were struck at the San Francisco Mint. The set contains a 90% silver Half Dollar, a 90% Silver Quarter, a 90% Silver Dime, a Jefferson Nickel and a Lincoln penny. Harder Set. This set is in the original government packaging with the COA. The coins were placed in individual spaces in a black cardboard. This was sealed within a plastic lens with the word “Silver” imprinted.