The line shown on the second page here:
https://rezoning.vancouver.ca/applic...elevations.pdf
probably doesn't indicate slab thickness, but slab edge.
The west elevation shows that the mechanical level steps back on the north side, so that may be the lip/ledge of the roof.
If it is a full floor on the north side, as built, then they may have changed the plans?
Either way, I don't see any more concrete columns up there. If the mechanical enclosure is yet to be built, it could be steel frame.
In my last pic there is still some formworks on the west side of the elevator core, but I haven't seen it move up recently.
Note that the crane does look higher than usual if it is topped out, but that could be due to surrounding clearances.