It is true that they are all prewired. If you have the lock/unlock button on your dash then you have the solenoids in the door and it is a matter of having the receiver and the keyfobs. Most of them had the receiver anyway and the keyfobs got lost along the way. The way to tell is to yank the glove box and look for a black receiver module that is more or less located on the passenger's side A pillar - just behind the front of the glove box. It will say Alps Electronics and it has a green plug in the bottom.

If you have such a module you need to read the fine print on the module to find the part number and FCC identifier so that you can get the correct remote keyfob.

...Lee