Which, in any event, would be immaterial. If born in the USA, Obama's claim to citizenship would be unaffected by any actions his parents might have taken when he was a minor.
Even if adopted and granted Indonesian citizenship, Obama would remain a US citizen -- unless he renounced that citizenship upon reaching his majority.
It is true that it is immaterial to his US citizenship status, but it is not immaterial to the whole issue. Adoption seals the original records and ordinarily results in replacement records being created. The oddities in that document which purports to be Obama's birth certificate can be explained as being the consequence of a state created replacement birth certificate. The normal practice is to make them resemble the typical birth certificates issued at the time of their birth.
One serious and obvious flaw in this one we have seen is that the certification is very different from what was used in 1961. In 1961 they certified it to be a "true and correct copy of the original."
Nowadays they simply certify it to be a copy of whatever they have in their records, and that is a very different thing. You can put whatever a judge orders into the record, but there is only one original.