Errrrrm! IF a wing was fitted with 8 screws - and it doesn't matter who's aircraft it is - and only 2 were in place. Why did Boeing fit 8 instead of 2 if only 2 was OK?
I would say that it DOES impinged on the integrity of the wing - it will increase vibration for one thing.
It says that the design required said screws and said screws should be fitted. OK, MOL's and MEL's have many things that are allowable but I defy anyone to show where it says that 6 screws missing from a wing series is acceptable.
And smudge it was not just one screw - was it?