Did your spoiler come with those mounting brackets still intact? How about the white slider locking tabs?
Too bad I did the removal over the weekend and didn't bother to sketch a template. If I were to install the aero pieces again, I would just use double-sided tape in addition to the screws, these holes are not pretty [I haven't tested the holding strength of tape on a chin spoiler at highway speed, but the hood chrome trip is taped on and holding strong
I hope these pictures help you in some way.