I don't know Perret. Is it possible that he was simply parotting Caro?

Perret's "Old Soldiers Never Die" was published in 1996. He cites Caidin's
"The Mission" specifically.
Of course, there is always the possibility he is lifting the info and citation
from another work. That's a fairly common way for authors (or students!) to
pad out their list of references. But Perret's speciality is writing from
original sources wherever possible, and he seems to do a good job of digging
out previously unaccessed documents so that he can present fresh insight about
oft written about subjects (Eisenhower, JFK, MacArthur, Lincoln, Grant).
Still, the Caidin cite leaps from the notes.
Caidin may be cited as freely as he is by more serious writers simply because
they can't imagine someone writing about serious subjects (such as
then-president Johnson) would simply present flights of imagination as fact,
that he would freely "adjust" a story to make it a better read.
Since Caidin embellished to make his subjects look better, not worse, he tended
to get away with it. Few feel the need to defend themselves against praise,
even when undeserved.



Chris Mark