The ark was a chest. A floating box.
Okay.
Affirmative on the tops of the mountains, though I don't see the relevance.
The relevance is that if there never was a Flood, then it doesn't really matter to the historian what any version of the Flood story says.
And there wasn't really a Flood, for a whole host of reasons, including that the Flood requires a flat earth and a magical source of water, and would have left huge amounts of unmistakable evidence which are simply not there.
So to return your OP, where you said:
If you read an article in Time magazine about some event and then later read a more detailed account in another article by another publisher it wouldn't indicate that the event didn't occur or that the later publication copied from the first. It's that simple.
I add the observations that ─
the many similarities between the Gilgamesh account and the biblical account, and the existence of the Gilgamesh account earlier in time, persuasively point to the biblical account being based on the Gilgamesh account,
if the Gilgamesh account is fable then it follows that the biblical account is fable, and
the Gilgamesh account is indeed fable.