Maybe a call to Axiom is in order. That's called a bucking magnet and is not really important just a different way of doing things not necessarily better. Are your newer speakers HP's , the cast basket is something they started do for people that feel cast is somehow better. It may aid in cooling the voice coil on a bigger woofer used for bass but on smaller ones there really is no difference. The ones in my car are plastic and I paid 350 for them. I think you will find the rivets are from the inside and to access them will require the cone to be removed, so it will be a big can of worms. Axiom makes their own drivers so call them and see what they can do.
