They are proposing to replace the galleria roof of the skywalk, yes.
This is one of the earlier images associated with the plan, and I'm not sure the design still holds exactly, but the idea is that the skywalk needs to expand to accommodate the numbers of people who will be using it (especially if the UPX is popular). The new design widens it a bit and adds volume. It also cuts down on how much the skywalk will heat up when the sun is shining upon it; currently it's not shaded by other buildings.