The GS interior is all leather, and it is not vinyl coated leather, its uncoated leather.
Auto manufacturers generally use vinyl on seat parts that don't get touched (the back of seats) but the seating surfaces, the armrest, the steering wheel, the shift knob, the door inserts, and the console base are all leather.
The LS for instance won't have any more leather than a GS unless it has the upgraded interior package.