Skip the dash LED "kits" offered by Scott Drake, LMR, etc. Go to superbrightleds.com and buy your own.
Get the bright ones for the back lighting (5 required) and the not-so-bright ones for turn signals (2) and warning lights (2 for 1982 GT -- seat belt and brake warn).
There are blue covers (through mid 1983) over the bulbs for backlighting and since incandescent bulbs give off a slight yellowish color the lighting looks green-blue. If you want to keep that look go with yellow LEDs. If you want straight blue keep the covers and go with white LEDs. OR remove the covers and get your color of choice (blue, green, white, red, orange, purple, etc) that will backlight the gauges with no color filter. If you change the color keep in mind that the clock and HVAC panel will still be green-blue an they are not easy to change.
For the turn and warn lights I recommend white LEDs.