Hmmm. Ellison disputes some of their recollections about City, especially about him being drunk, since he doesn't drink.
Skimming Ellison's book, it seems he mostly agrees with the Solow/Justman version of events. However, Ellison draws exception to this passage at the end of Solow and Justman's chapter dealing with 'The City on the Edge of Forever':
Some years after receiving the Writers Guild award, Ellison was in a bar when he ran into writer Don Ingalls. 'Fandango,' a script Ingalls wrote for Gunsmoke, was one of the four other contenders that lost out to Ellison's script. Ingalls had also written for Star Trek, and they discussed not only the series but Ellison's award-winning script. After a few drinks Harlan boasted that, before submitting his own final draft for consideration, he had 'polished it up a little bit to make it even better.' To this day, Ingalls remains amused by his friend Ellison's award-winning stratagem.
--Herb Solow and Bob Justman, Inside Star Trek: The Real Story (1996), p.289
...this anecdote never happened.
Not any part of it.
Not a bar, not me being drunk, not hoisting a few with a guy I barely knew, not doctoring up my teleplay so I could enrich my chances to win. It's all bilge and rat-puke.
--Harlan Ellison, The City on the Edge of Forever (1996), p.73
Ellison goes into more detail, but the long and short of it is that he doesn't drink, barely knows Don Ingalls, and still has the copy of the script he submitted to the WGA, which is exactly the same as the one he turned in to Star Trek
(Tellingly, Ingalls -- who wrote 'The Alternative Factor' and 'A Private Little War' -- was a good friend of Gene Roddenberry. The two worked in the LAPD together before becoming writers.)