Definitely clean, we even had all our furniture delivered and the builder (or his men) set that out as well.
We had 1 room (the bathroom) where the tiler had just wiped the walls following grouting, but he only gave it 1 wipe so we had dried grout on all the tiles, I said I would sort it and thought it would only take an hour, it took me all day the hardened grout really sticks.
The car analogy above is good, you never buy a dirty car from a showroom.