I would dismiss any book claiming to be a historical record if it was written based solely on word of mouth accounts, a century (and more) after the events it purports to record, particularly when it was put together from a multitude of accounts, yet only a select few (and those selected by the very people claiming it as their text, as opposed to being selected by, say, impartial scholars) make it into the final story.

That would be a bit like writing SA's current political story 100 years after the fact, based only on the word of mouth stories of the Zuma clan. You're not going to get an accurate historical record that way. So yes, I do dismiss it quite comfortably. Besides, when you talk of historical situations, you always have evidence to back it up - where is the evidence god exists?