1982 380sec, missing part on air cleaner?
 

I was working on this car for my neighbor, it has been sittng for years and I replaced the fuel pump and got it started, but I noticed there is a gromet on the top of the air cleaner and it looks like whatever was supposed to be there is gone. (can be seen in this picture) http://i735.photobucket.com/albums/ww351/mercedesbenz911_photos/Parts%202/1595dd15.jpg

What is supposed to go there?

Nothing. It is the access to the fuel mixture adjustment with the air cleaner installed.

Hmm that makes things easier, this is the only gas V8 car in running condition I have seen under the hood of so I wasn't sure.