If you have time, please read the article at the link;
http://www.wnd.com/index.php?fa=PAGE.view&pageId=105817
Corsi's article is a pile of red herrings, designed to raise groundless suspicion. Starting with, it's for sure 6 June 2007, not 8 June, as Corsi incorrectly concludes using the inadequate original scan. It's a total waste of time to analyze that original scan.
Here's a better photo of the seal and Dr. Onaka's declaration.
If the document is forged, then I would have expected the Hawaii state officials to have called Zero out on it, or referred the matter to the DoJ, or at the very least to have failed to vouch for him being born in Hawaii in order to protect their own reputations.