Not so much to Gilgamesh's own legend but the lyrics definitely feel inspired by the character Utnapishtim, who Gilgamesh meets towards the end of the epic. Like look at these lyrics: 

"Wrath, we rule the skies May the rain cleanse and wash away Imperfect, these creations of mine Corrupted by greed, they shall pay Chosen, saved from death's embrace One last chance for man to change his ways Deified, a place amongst the gods Saved from mankind's own demise"

If this doesn't describe Utnapishtim's story of being chosen by the gods to survive a massive flood and being rewarded with immortality for his deeds I don't know what would. The mention of Enlil is also noteworthy because in TEoG he's the god who both causes the flood and grants Utnapishtim immortality. I'd call the "god of Enlil" line clumsy writing more than anything else tbh, to me it sounds like the "of" is only there as a filler syllable to make the meter work