No, this does not solve anything except cosmetic issue with naming. Device minor number is still wrong. Also you now have it 'right' only for situation when you boot with external card inside slot. Once you remove the card and boot it will be wrong again.
Is there some OS that automounts second partition on mmc card (formatted as ext2)? At least Windows does not see past first partition on removable devices so this does not matter much. But of course with linux one should not mount same partition which is currently booted.
Using your tips page I've verified that the MMC swapping problem is not affecting my n800. You used the Maemo wiki to clone your card. Those instructions are only intended for 2006, 2007. Did you follow the one for OS2007?