How to replace rear speakers in 98 astro?

i have a 98 chevy astro (trunk doors are french door style not hatch back) and the speakers are blown. i think there stock subs because they only produce deep sound like a sub. but anyway there blown and i need to replace them. but it seams like there is a rivet of some sort holding it in. but it might not be a rivet. anyone know how to take the speakers out without having to cut the door?