Totally! For a meeting between a spymaster and a terrorist leader? Heck yes! It's just to serve as a nudge for the spymaster's memory, it's shorthand code as a precaution. If it had named Atta, it would be much LESS convincing.
Well, I wasn't thinking that Atta's name would appear, but that the entry would have included a fake name. That would have been less suspicious that an entry with no name.
Of course, maybe there was a fake name. We really don't know.