Fwiw, my 108 had plugs but they were cone-shaped with a drain hole.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

Coincidentally, I have been trying to figure out the part number for the rubber grommet that goes at the bottom of the spare tire well for a w115. After WAY too much time looking, I believe it is 1119971281. You can see a picture of it here:
TAPERED GROMMET FOR WATER DRAIN ,111 997 1281,,111 997 1281,1119971281
but don't pay that price. It is cheaper via PP or the dealer.

Given the part number, I assume it is also used on a w111. I suspect that is the cone shaped plug that Tomguy just mentioned.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

That's it indeed. If it was used on the 108 I can't see why it wouldn't work on the 111. I doubt they changed the size of those holes.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

That's super strange (and annoying) in EPC. If I search that part number it shows up as being what you say for lots of models. What is strange is it shows that on a 110 for the US but not a 111 for the US, but ON a 111 for Japan. Silly EPC.