but I don't know that I buy it.
In 1957 the book was published by Feltrinelli in Milan, not anonymously. The US edition was in 1958. Hardly simultaneous publication. Pasternak wanted Feltrinelli to return the manuscript he had. This implies that either the CIA acted as Pasternak's agent, or the CIA's role is much inflated.
Here's one report at the time, between publications.
http://www.time.com/time/magazine/article/0,9171,810175,00.html Whether or not Feltrinelli was, indeed, a communist, I don't now. Of course, one could say that this is revised to support the usual history, but it would be far too embarrassing for archived copies to be at odds with the on-line version.
I have no evidence that Ivan Tolstoy is any relation to the famous Tolstoys from the 18-20th centuries. 'Tolstoy' is a common enough name, a dialectal version of the word for 'fat' or 'thick'. In my preferred transliteration (which would have the writer's name rendered 'Tolstoj') the usual word is 'tolstyj'. If the reporter had provided his patronymic we'd perhaps have a clue.
My first response, given the documentation for the traditional version of events that I. Tostoy disputes, is to ask to see the letter from the CIA agent and have it validated. If not, we're left with somebody saying there's a single anonymous report that the other documentation is wrong. This merely smacks of yet another effort to say anything embarrassing or bad that happened to the USSR/Russia was the result from the all-knowing all-powerful CIA. There's certainly no shortage of that in Russia nowadays.