You're pretty busy today Max and I'm real interested to see so I'm just going to plug in my PS2 and see if I can find those elusive chakrams (I'll see if I can't get a picture as well but don't hold me to that).
EDIT: Ah ha! I did the last fight and Max was right. It's only in the first fight against the armored Xemnas though. Not the second one where he throws the buildings at you. Sai'x and Xigbars' weapons are also there. I can't get the pictures up now. I'll have to try it later.
I'm just happy to know that I am not crazy, you actually found it! Not only that, but you found other weapons as well. I only remember Axel's chakrams, so now I want to take a look and find the rest haha