1971 United States Proof Set, 5 Coins Inside!!. The 1971-S Proof Set was again a Proof Set collectors dream. Another "S"-less coin was discovered, as well as a few very rare Doubled Die varieties.Each set contained five coins: One example each of the Lincoln Cent, Jefferson Nickel, Roosevelt Dime, Washington Quarter, and Kennedy Half Dollar.About the sets: 1971-S Proof Coins are found with Brilliant, Cameo, and Deep Cameo surfaces. None of the new Eisenhower Dollars were included in the 1971-S Proof Sets. However, Proof 40% Silver Clad versions of the 1971-S Eisenhower Dollar were available separately. An estimated 1,655 Proof 1971-S Nickels were struck without a mintmark. Although Proof coins were being struck at the San Francisco Mint at the time, the Philadelphia Mint was responsible for making the Proof dies (and adding the mintmark). Apparently, at least one die was sent from Philadelphia without the mintmark, and a small number of "S"-less Nickels were struck and released before the error was discovered. The mintage figure, provided by the Mint, was apparently based on the estimated output from a single die pair. Because the "S"-less Proof sets are very valuable, be sure to examine the plastic case for signs of tampering and substitution. Do not purchase an individual "S"-less Nickel or complete Proof Set unless it has been authenticated by an expert.