I wouldn't think so, generally lighting wires are not that thick. You can always test the wires with a multi-meter. Just put the car in reverse and test lines for 12 volt power, when you find one take the car out of reverse. If the power goes away that is your reverse wire.
Easiest place to get the reverse wire is to grab it at the rear of the car on the left side. Unfortunately I can't remember what color it is right now.