I'm about to do the same to my 73 'Cuda... I have to add a mounting bracket to mine, but then I'm going to drill a pilot hole to ensure I'm not off the mark. Then widen the hole to the same size as the hole in the upper metal plate (maybe a tiny bit bigger to be hidden by the plate). I figure you don't want the hole smaller as it will not be covered up by the plate and too much bigger may cause other problems.
Be sure your hood is adjusted (aligned) where you want it though... Mine has a lot of play and if I'm not careful I could put the hole in a bad spot.
Alan