Evanix Rainstorm ii Shroud

I recently purchased a refurbished evanix rainstorm ii from PA. When I took the shroud off the only thing in it is a small disk, a spring and a single baffle. This is at the top of the shroud where the end cap would screw off….if i could get it off. My question is is this all thats suppose to be in there? And is there anything i can add to it to help lower the sound ? Thanks in advance