GX has a panoramic roof option. I'd guess the LC shares the same option for the roof since they appear to be a shared product. Would be very easy for Toyota to take the pano roof and make it one or two removeable panels. Not sure it's very likely that they will, but the structure is already there. So it's possible to do without major engineering work on the body structure.
However - the bump you see there is the stamping in the non-sunroof roof panel. You can see below that the GX550 without the sunroof has an separate set of stamped structural elements up front. If you look close you can also see the three mounting points for the roof rack with the rubber caps on them on the image without the sunroof. I'd bet that that is the same roof in the teaser image (no sunroof, no roof rack):
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