Panama in 1973. In this mated pair, coin #1 is a
1973 Panama Tenth Balboa die struck both sides by the Panama dies on a U.S. clad dime planchet. In 1974, also at the San Francisco Mint, two obverse Lincoln Cent dies, both dated
1974-S, were paired together and installed in the same press. If a copper cent planchet had been struck by this die pair, a two-headed Lincoln cent would have been produced. To date, none have been discovered. This 1973 Tenth Balboa was placed in the collar of the press containing the two obverse dies for the 1974-S Lincoln Cent, on top of a copper cent planchet already seated in the collar. These were then subsequently struck together (mated).