Kbuzz, Brass is not magnetic. Stainless steel is not magnetic either. Test the screws with a magnet.
Cheap tweak from Virtual Dynamics:
Has anyone seen the short video from Virtual Dynamics showing the owner replacing all his speaker screws with all brass screws? I was wondering if you could hear an improvement. It's a cheap tweak, so I thought I might go to Home Depot and try out a set. What can I lose?