sbourg seems to be right.
According to notes I found for an "83" 380SL (which I assume is the same), you need to install an acutator in the driver door. Looks like its the only one you need.
I found this website over the weekend and called the guy. He said if you buy from him that he'll help you through the install. He should have access to all of the wiring information for your vehicle. I have not purchased anything from him yet nor do I know him personally.
http://www.startbyremote.com/