The papers received a report each week from the Bureau of Vital Statistics listing births, deaths, marriages and divorces, statistics the Bureau gathered from hospitals, funeral homes and courts. In turn this information was given to the papers and then printed each Sunday.
It’s not unreasonable to expect that the Bureau of Vital Statistics would provide info from COLBs filed as well.
And I believe that his mother was crafty enough to want to make sure she registered his birth in Hawaii so he could be a US citizen. She was no dummy. Radical, but not stupid.