In the past few months, windows and the facade have been installed on all sides of the building, though Hurricane Ike tore away some of the insulation components around the 15th & 20th floors before they could be covered up.
Since then, they've made significant progress installing the actual facade over the internal materials.
Here are some photos from this morning.
Looks like they're putting up the supports around the mechanical penthouse and along the top floors of the western facade for the "fin".