Exactly, its a simple narrative in a simple way that non scientific peoples would identify with, the details are fuzzy because its not intended to be a scientific paper on the matter but is intended to convey a far more important and deeper message. At least one of those is that of the Sabbath day.
Yup, some cultures had 4 day week other 5 etc. the Babylonians likely picked up the 7 day week, if they took it seriously, via Daniel which would put that at around 600BC. They had the eclipse or Saros cycle figured out before that.