Inorder to link K2 items, we need to have K2 Menu Items.
so the Joomla Menu Items that we had already created are not useful for those who would be solely using K2. is that true?

but lets says i have a menu name from joomla kay2
now i create a new menu using K2 and call it kay2
would that duplicate my menu items?

You would probably run into title alias difficulty, change the name