History and storytelling are intertwined in these narratives. First, there likely was a King of Uruk named Gilgamesh. This name appears on the Sumerian Kings List. The epic itself does not tell us much about actual life in the region. Polytheism, the belief in multiple gods and/or goddesses, is an important part of both narratives.
"Who is the mortal who can live forever?
The life of man is short. Only the gods can live forever."
From the Babylon Creation Myth:
"One god is greater than all great gods, a fairer fame, the word of command, the word from heaven, O Marduk, greater than all great gods, the honor and the fame, the will of Anu, great command, unaltering and eternal word!"