To me it looks like the rivets are all in place and some other screw(?) should be in the larger holes.
If it had been me looking at it, I think I'd have pointed it out to the crew and asked if it was ok. In the mid-80's a plane crashed on takeoff from Denver due to wing icing. I wonder if any passenger looked at the wing as the plane was taxiing and wondered if the ice on the wing was excessive but didn't say anything.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13