I have 1981 380SL. It had the common issue of the trunk button malfunctioning. Instead of researching a solution, the previous owner drilled it out. So it's toast. I removed it and put the latch back in. I can reach through the hole and push the catch with my finger and pop the trunk open. I am not spending $500 plus on a used button.
Has anyone put an electric popper in place of the button? How did you do it? What parts did you use?

 

Keep searching. I saw one on flea bay without a key. Part number for replacement with key is 107 750 12 85