Chronologically, this was actually the first "injury". But it was not claimed at the time.
Instead, it became the third claim -- urged by his fellow officers -- which allowed him to gain "three Purple Hearts and out".
This according to the "Swift Boat Vets".
Agree that the chronology is mixed up. For FR readers, see Chapter 3: The Purple Heart Hunter and Chapter 5: More Fraudulent Medals, in “Unfit for Command”, by John O’Neill and Jerome Corsi (and Scott Swett and myself).