I see what you're talking about, but the cover would be mounted to the 2 top metal "flanges?" either side of the neutral bus.. & those aren't clean like the locations I think you're referring to... If I remember right, & if I'm looking at this right, this is a GE 3phase (400A?)panel.. Isn't the deadfront attached to the panel cover??
What was bolted up there??
Looking at this again is making me think something along the lines of a forklift skid.. The blown out section looks about the same size to me...
Tim, I've some across water damaged panels before also, but this is one hella blowout!
PS Bob, don't forget to reidentify the white on the top breakers (Ckts 1,3,5 & 2,4,6)