Out on a really strange limb here:
Just a hypothetical — suppose Stanley Ann needs a certified BC to gain full custody from Hawaii courts in 1964. She doesn’t have one and there was no official one filed wherever the kid was born. So she — or her parents — get in touch with someone who can help.
We need to be looking at connections between the Dunhams and their friends/family working in Australian vital records in 1964.
The B.C. Orly has may well have been manufactured in Australia in 1964.
Or by a family friend/relative connected to the Harvard Law Review.