Great point. I have a 94 18" with factory decals but they are the All Terra. If you look at the blue frame above, the "G" in the GT decal on the downtube is below the lower water bottle boss compared to the Zaskar in the ad from the link which is a larger frame. The "G" in the ad lines up with the lower boss.
Also, these were applied by hand and from multiple employees so I'd expect there was inherent variability within employees.