Help identifying fender nut/clip

[gonesurfing]

In the process of doing some extensive rust repair on my first benz, a '78 300CD. Each fender has two mounting points on the rocker panel where metal spring clips engage the screw. I cannot for the life of me find it on any parts diagram or anywhere on google. I'm sure there is a terminology I'm not searching correctly for, but "nut", "clip", "retainer" are coming up empty.

Attached is a picture showing the location and (damaged) clip.

Thanks in advance.