They blanked out the certificate number so that it wouldn’t be an “official” copy. That would be forgery if it was fake.
Here’s another possibility ...
If his mother needed to reside in the U.S. for five years before his birth, did Hawaii “count” when it was a territory or only after it became a state in 1959?
Just curious ...
I saw commentary on one thread that suggested they blanked out the certificate number because it was "blank", that the certificate was filed but never accepted by the state of Hawaii. I wonder if thats true that cert #'s are only filled in when the certificate is accepted?