The clear trend for curtain wall installations in New York is a unit approach, where mullions are joined in the factory to the insulated glass units with joints that allow each curtain wall unit to join to the previously installed units to the side and below, with the exterior finish of the mullions integral to the preassembled unit.

Less common today is the previously standard method of installing the grid of mullions first and then installing the insulated glass units, as shown in this new building going up on the East Side. The decision to revert to the older method here may be driven by the exterior finishing of the curtain wall joints, yet to be executed at this stage.

The panels to the left in the above image appear to be terra cotta, which may suggest a rain screen system for that portion of the envelope.