I use masking tape to mark the center of the holes and follow him previously said Kevin; this cover is steel, by making these holes will rust.
maybe this will can be helpful:
http://www.hdforums.com/forum/dyna-glide-models/635396-cheap-under-10-air-filter-mod-for-more-power-and-style.html...
Hello everyone, my name is Francisco and I'm from Spain, I love DIY tasks in general and to me really liked this forum, there are a lot of quality information and other things that can be of great help ... It's good to be here. A greetings to all!!!