We have a new to us 116, and like the 123 that tool does go on a fitting about 4 inches aft of that tool bracket to open the sunroof manually. The car manual shows a tool to use with it (maybe it is the tire iron, but it could be another small bar that fits over that tool).

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'85 300TD W123
'83 300D W123, Daughter's
'80 300SD W116