One goes at top the other at bottom of page as you get posts into your guestbook so if the page is long people can just click the buttons at bottom and not have to scroll all the way to top to go to another page or something
Correct, there is one at the top and one at the bottom.
As nobody has posted there is no space between them. I tried to put a test post on to show how it would look with posts but you seem to have the guestbook set for preapproval.