The Kennedy half dollar underwent a number of revisions after its early-1964 debut.
With the 2014 release of the 50th Anniversary Kennedy half dollars in .9999 fine gold, .900 fine silver and copper-nickel clad versions, the obverse returns to U.S. Mint Chief Engraver Gilroy Roberts’ 1963 sculpture, based on an earlier medallic portrait of President Kennedy. The version used, however, is not the 1964 Accented Hair design variant.
When the first Proof 1964 Kennedy half dollars were struck, the end result is what collectors refer to as the Accented Hair variety. Additional strands of hair above Kennedy’s ear help form the appearance of an inverted wishbone.
According to Numismatic Guaranty Corp., to attribute the Accented Hair variety, look for the “frosty W” shaped pattern of incuse lines in the hair above Kennedy’s ear to identify this variety. Examples of the Accented Hair coins can be found unattributed in 1964 Proof sets.
Another obverse diagnostic is that the I in LIBERTY on the Accented Hair variety is shorter when compared to the more common variant.
It has been written that the slain president’s widow, Jacqueline Kennedy, was dissatisfied with the Accented Hair version and requested modification.
Some researchers suggest that 1 percent to 3 percent of the Proof 1964 Kennedy half dollar production is from the Accented Hair variant. The extant population of Accented Hair coins is suggested at between 40,000 and 120,000 coins.
Since its introduction, the Kennedy half dollar has been subjected to annual evaluation to determine if any modifications should be made to strengthen design details.