Well, it is hard to estimate, but from what picture I would not be too worried, it should be equalizable with the screw.
However please note that I have no practical experience with this situation. I have come close however when I bougth a second hand guitar with a Kent Armstrong neck humbucker where one of the screws had somehow fallen into the pickup (picture that!). There was immediatly noticable drop or anything on that string. It was a slight bit different, but without looking at it in perticular it would have taken me days or weeks of vague discomfort to figure out what was going on (if that).
So yeah, I, as a tweaker of screw heights and such, would say that the difference is probably minute enough to look over or to make up for easily.
