One discrepancy, possibly too strong a word, between Averbakh's account and Mikhail Tal's recollection can be found on page 112 of the English edition. Averbakh relates how the grandmaster title was awarded to the then USSR champion Mikhail Tal in exchange for also awarding it to the then US champion Arthur Bisguier.
On page 63 of The Life and Games of Mikhail Tal (first English edition, RHM Press, US; Pitman, UK. ISBNs: 0 89058 0278, RHM; 273 014 90 3 Pitman), Mikhail Nekhemievich wrote:
During the championship of Europe a FIDE Congress was held, and our Federation proposed me for the title of International Grandmaster … I was 'exchanged' for L. Evans and A. Bisguier.
I've checked the Russian text of Averbakh's memoirs. There is no mention of Evans. Many years ago I had a conversation with the late Bob Wade about this deal. Unfortunately, he could not remember anything about it.
Tal was awarded the title in 1957; the same is true of the two Americans.