Just speculating on how a late birth registration would be reflected in the issue of a birth record number. The odds point to it being a late birth regisration. If so, then there's no way that Obama would have gotten a number that fell within the series of birth record numbers given out to on-time, birth registrations in 1961.
See the logic?
We could cover this ahead of time by asking Freepers who know Hawaiians born in 1961 and just get their birth date and document index number. If his document is out of order, that would suggest a forgery.