Sam, im not gonna be much help, but ill try. first off, obvious- do you have a buddy who has the same vintage car that you can look at? might want to check the other door, and see if the wires are the same color (i cant remember myself). if they are the same for each switch, mimic what it is on the other side.
your lock wire should be pink/light green, and your unlock should be pink/yellow (im not 100% on this; it's based on recollection from an alarm sheet for 86's). now that seems to be the same as my 88. i have a donor driver door for my 88 gt in the garage. i looked at the switch. if you hold the switch with the buttons toward you (like you look at it in the car), then turn it about face (so youre lookin at the back of it), the wires are as follows: top left-pink/yellow. bottom left (directly below it) is black. in the middle (dead center) is Black with white stripe (the stripe may be silver, etc-the wires are faded from the sun). in the top right is black. in the bottom right is pink/green. since the trigger wires are the same colors for both of our cars, im thinking the rest are the same (IIRC, they both use reverse polarity locks.). so if you have those same colors of wires, sounds like a good bet.
NOTE: im not telling you this is 100% reliable; test all wires first, try this at your own risk, i assume no responsibilty, yatta yatta yatta. that said, im pretty sure this will work for you if you have the same color wires. i also have one vacant slot (6th slot), as you do, BTW.
hopefully someone else can shed more light into my info here and provide more assurance about my thinking.
sorry, thats all i got. good luck.
