Doug,
The contents of this option varied from year to year. Are you speaking of a 1968? Upper consoles were part of the interior decor group or commonly called a deluxe interior. The lower console was a separate check mark on the option sheet to the best of my knowledge.
GT options normally involved suspension and braking upgrades. The GT option was tied to only certain engines in the earlier years. Later (67) they could be added on more of the common motors. Typically the GT option ended up on the more high performance engines, but not always.
In 65 and 66 the GT option could only be had on an "A" code 4 barrel 289, or a "K" code hipo 289. It consisted of higher rate front and rear springs, disc brakes, GT badging, dual exhaust with special rear valance, fog lights, special stripes, and larger sway bar. In 65 only it also included the five dial instument cluster that came standard in 66. In 67 it could be added to a "C" code 2 barrel 289. Similar options to the 65/66 with the dropping of the dual exhaust.
In 68 it could be had without disc brakes and with single exhaust again. Not sure of the engine options for 68. In 69 only a few early cars were GT's. Not sure of those options. The GT was replaced later in 69 by the Mach I option.
All of this to the best of my knowledge and research.
Rob