@joecat – From what I see it looks like you only need to register the sidebar if you want to have it widget ready. If you code all the functions you want added to the particular sidebar and don’t need widgets added then it is not necessary. More info on this is in the post of the codex. http://codex.wordpress.org/Customizing_Your_Sidebar It is located a little more then half way down the page after the heading ” New way of adding sidebars”
Hope that helps.
