Well, two are probably for the coil and the third is likely connected to the cover for shielding purposes.
Take your digital multi-meter (you DO have one, right?) and measure the resistance between each wire and the others. Write it down and keep it with the case that the pickups came for future reference.
(Wiring a guitar without a digital multi-meter is like driving with your eyes closed. Just say no.)
For the two wires connected to the coil you should measure around 5,000 to 10,000 Ohms. If the third wire is connected to the cover, you'll measure around 0 Ohms from the nickle silver cover to said wire. If all three wires have 1,000's of Ohms to each other, the third wire is a coil tap.
As I mentioned, measure between all three wires (6 readings, three of which should be redundant) and the cover and post the results.
I suspect that the third wire is the cover shield connection because these are custom shop pickups that may be wired with the Tele 4-way switch and would require a shield NOT connected to either coil wire for the series coil mode.
As to the meaning of each wire color, I don't pay attention to such until I wire things in after measuring everything always anyway. Others aboard will know such detail perchance.
One of the bridge pickup wires will probably be connected to the bridge plate thru the mounting screws to effect the bridge plate ground connection.
Thanks a lot to RJB and especially to ChrisK for taking the time to give a good answer. I do have a multimeter, and I am printing out all of this info for my project. I will be back both to give and receive the good advice found here.