I think some have said the account was an inspiration of Moses. He takes credit for the first 5 books of the bible.
The movie "Noah" that came out a while ago suggested that he was inspired to write about the creation story. I believe the WT believes this version because they had an article about an ancient Genesis record being passed on from faithful person to faithful person. It's been a while since I read it. I'm not sure if they think Noah got the whole story downloaded into his brain. WT probably thinks it's more like this: Fallen Adam tells Seth. Assuming the creator had a 1on1 with Adam before the fall => Seth tells Enoch => Enoch tells Lamech => Lamech tells Noah => Noah tells Shem => Shem tells Abraham => Abraham tells Issac/Jacob => Jacob tells Levi => Levi has multiple offspring and it is passed on to Moses.
I'm probably missing some in between people. Enoch may have been dead before Lamech. I can't remember.