Yep.
If you ever re-drywall, you know that drywall dust falls from the air for at least three month in your home.
An open window or opening or older property would dust a lot.
If the home looks clean except for even layer of dust, then it is just natural. If the dust is sitting on top of massive clutter and hair bunnies or built up in some areas, like behind doors, then your friend is also pulling your leg.