Having such a Wii myself (and hating it because of crippled homebrew support) I know that:
1.It shows 2 disks. For it to show 1 disk (like on vWii and presumably the Wii Mini, as they are not upgradeable) there would need to be seperate system menu versions for normal Wiis and GCNless Wiis, which would be a mess all for the removal of one graphic.
2. Yes, it does. I recently deleted mine because the System Menu told me that my NAND was full