A circa-2017 site plan shows renovations done over the past 3 years. These have added a new Saks store, West Wing (in gray) and "jewel box" retail building (in the northeast parking area). Being as how the GALLERIA III section no longer exists, one could surmise that the old GALLERIA I, II, III and IV designations are no longer in use.

The new (and relocated) Saks store encompasses 2 levels and 198,000 square feet.
Drawing from Saks, Incorporated

The old (and now reconfigured) Saks has been repurposed as inline store and restaurant space.
Drawing from www.simon.com / Simon Property Group