I'm looking at a 78 240D that's been sitting a while
Though on the exterior the body looks near perfect
It has the classic floorboard rust
Particularly bad on the drivers side where it runs along the point where the floorboards meet the sides (where the seatbelts mount etc)
I have fixed this sort of thing before using sheet metal, pop rivets and seam filler and it worked well
The rest of the underbody looks pretty good as far as I can see

I noticed that the gap on the backside of the drivers side front door is noticable wider at the bottom than the top. Perhaps as much as 3/16" difference. This door doesn't seem to latch, though I noticed that all the door latches are stiff and need lubricating
This made me wonder

My question is:
Is it common/possible for the W123 bodies to sag in the middle ?
Or is it likely just the drivers side door sagging a little?