I'm not sure how far I'd take this kind of corroboration. In any good work of fiction the author tries for as much versimilitude as possible by adding as many "real" details as possible. For example, Clancy's books - total, if fun, fiction if there ever was some - have a lot of true details added in the scenes he presents. One which had a scene from London had street names right, shop names, bus lines, etc. It's still fiction. No reason the professional story tellers that invented the stories that were amalgamated into the OT wouldn't be as good. Especially if there was either a popular mythic, legendary or even real person they could throw in.
Picture this (a kind of
reductio ad absurdum, but an interesting thought piece anyway): 2000 years from now someone digs up a copy of "Sum of All Fears". Although English is a dead language, it's still taught alongside really ancient Latin, so there are people who can read it. An archeologist digging around the former site of ancient London finds street names, even a shop sign identical - and in the identical place - that appears in the book! Would this person then be justified in claiming that the book represents a true historical account of the late 20th Century? Sound familiar to anyone?
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