http://www.icr.org/index.php?module=articles&action=view&ID=414
Where do your get your 7th century date? "The actual tablets date back to around 650 BC and are obviously not originals since fragments of the flood story have been found on tablets dated around 2,000 BC"
Dating of the oldest fragments of the Gilgamesh account originally indicated that it was older than the assumed dating of Genesis.21 However, the probability exists that the Biblical account had been preserved either as an oral tradition, or in written form handed down from Noah, through the patriarchs and eventually to Moses, thereby making it actually older than the Sumerian accounts which were restatements (with alterations) to the original.
A popular theory, proposed by liberal "scholars," said that the Hebrews "borrowed" from the Babylonians, but no conclusive proof has ever been offered....
Reading the above carefully, you see an admission that the oldest primary sources we have make the Gilgamesh tale considerably older than the earliest primary sources for the Noah tale. They then handwave around this by trying to claim that somehow the Noah story was preserved *orally* more accurately than the written-down Gilgamesh version, or that hypothetical earlier written accounts existed (evidence please?). When they refer to "liberal" scholars, what they actually mean is "all scholars who didn't sign up to the inerrant truth of the Noah story before they looked at the evidence." Archeology like other sciences doesn't deal in proof; it deals in evidence. The Gilgamesh primary source is considerably older than the Noah primary source and remarkably similar to it in many ways (but not in ways that support the Genesis morality tale). The sensible conclusion to be drawn is utterly obvious to everyone who hasn't already signed up to the literal truth of Genesis. The Noah story is derivative of the Epic of Gilgamesh
The word "originally" in the ICR quote is particularly disengenuous. No contradictory evidence has ever appeared that would make a different conclusion from the "original" one valid. A casual reader might draw a different conclusion from this unnecessary word.
Finally, trying to get the truth about anything related to the age of the earth, geology, or biology, from ICR is a bit like trying to determine the truth about conservatism from Michael Moore movies.
To expand on my original answer, and to respond to the question that you asked rather than the website that you directed me to.
The earliest primary source for the old testament that we have is the Dead Sea Scrolls, which were written between 300BC and 100BC. We have a complete copy of the Epic of Gilgamesh dating to around 650BC, and we have fragments of the Epic of Gilgamesh dating to 2000BC, which would be only a couple of hundred years after the Noachian deluge, if the Bible's timeline were correct. Even the ICR site, a site that pushes Biblical literalist interpretation doesn't attempt to disagree with those dates. In the light of those dates the ICR's handwaving about "oral tradition" appears to smack of desperation.