I'm sure someone will come along in a minute with an accurate and extensive list but here is what I look for to see if its a GT.
Cruise Control - should have six buttons on the steering wheel. As far as I know, all GT's come with this.
You are correct with the seats, they should be electric but the switch for them is on the left side of the chair. Mine has those manual dials too, they are for the movement of the seat height and leg support thing.
It looks like the updated interior. The main way I can tell the difference is that the three dials have chrome details on them. One other good way to check is to see where the hazard light button is. If its just under the three dials infront of the gear stick, its the updated model. Mine (an 04 plate) has it way back on the centre console, near the seat warmer buttons.
Hope that helps.