I updated a few entries based on my new book (images were previously inserted by me).

Search for reference [232]. Image was added last year (2014). Image is of DDE-C2-07 (Class 2 Hawaii)

https://en.wikipedia.org/wiki/Dwight_D._Eisenhower

Search for term "appreciation medal". Image was added last year (2014). Image is of JFK-C5-02 (Class 5 Kennedy)

https://en.wikipedia.org/wiki/Kennedy_half_dollar

The JFK-C5-02 vs Kennedy half dollar eagle's tail Image is supporting evidence of what I call a "non-disclosure policy" by the Bureau of the Mint (now called the United States Mint). Discussed in my book (one of the reasons the Presidential Medal of Appreciation Award Medals are not documented publicly for over 57 years by the United States Mint).

It has been documented and stated that the Kennedy half dollar used the reverse of the Bureau of the Mint Presidential series stock medal #135 (known as the John F. Kennedy Presidential inauguration medal) to develop the reverse of the Kennedy half dollar.

However, notice the placement of Frank Gasparro initials "FG" on JFK-C5-02 and the Kennedy half dollar. "FG" is similarly placed under the eagle's right leg.  From this it can be said that Mr. Gasparro gained more experience from his work on the Presidential seal of JFK-C5-02 (larger and more intricate detail) and less experience from working on stock medal #135 (small and less detail). Stock medal #135 pre-dates JFK-C5-02. 

Lastly, notice the similarity of the torches with stock medal #135 (reverse) and the Class 2 medal (obverse). Frank Gasparro reused the dual torch concept from Class 2 medals to  stock medal #135. (class 2 medals predates stock medal #135). 

The Presidential Medal of Appreciation Award Medals are somewhat of a missing link for some of the United States Mint's coins and medals...