It suggests to me there never was an original...the ‘letter’ was made up on the fly, it doesn’t follow the speech he made:
http://www.youtube.com/watch?v=Trqfq9FY1Ig
Hawaii gov. seeks to combat birthers
HONOLULU For once the conspiracy theorists who believe Obama was not born in the United States and the president’s defenders are on the same page.
Neil Abercrombie, who was a friend of Obamas parents when the president was a baby, has only been governor of Hawaii for less than three weeks, but hes said in interviews this week that hes already initiated a process to make policy changes that would allow Hawaii to release additional evidence that Obama was born in Honolulu on Aug. 4, 1961.
http://www.politico.com/news/stories/1210/46797.html#ixzz19ALEthBZ
Well, some of the phrases in the letter were in Abercrombie's speech (including Kapi'olani as O's place of birth), but not Abercrombie's sign-off, "With great aloha, Barack Obama." Could well be that the letter was created after the speech to try to conform with it, not before. Suppose there's no way of telling definitively.