It may be one thing to have one side's political spin on an event and different details. It is another to have a completely diametrically opposite end result of the event.
Brutus killed Julius Caesar, not the other way around. Else we would not have had the Battle of Philippi, and all other subsequent events as a result of Julius Caesar's assassination.
Similarly, either Dulinor killed someone that had the role of Strephon in the palace, or his ship blew up before he ever reached the palace for his audience. This is not disagreement over a detail such as whether he took 1 shot or 6 to do the deed. Either Dulinor did the deed and the Golden Age of the Imperium ended in the fiery holocaust of the war of the Rebellion, or it didn't. However skewed or incomplete the records, I do not think people would forget entirely about the existence of a war spanning a good chunk of Charted Space destroying within a generation the largest interstellar state of the time, not unless we are talking about a huge time jump into the future, not merely a few centuries or a few thousand years.
And if we are, that does not really help us IMO. If it's that far into the future, post singularity or singularities, then how is it Traveller anymore if humans are unrecognizable to us and the Imperium might as well be cave paintings? If people are still people, and there have been more dark ages, then how is it really any different from another version of TNE wiping the board?