OCR does not turn it in to a computer created document. Where did the document originate? Obama says it came from a photocopy of his original 1961 BC. Yet, he did not post that. He posted a computer created document. Do you understand that? OCR also does not turn an ink signature in to a non-ink signature. OCR won't save you or the document.
We are viewing a PDF on a computer, so by definition it is a computer generated document. The question is whether layers are any indicator of what the original source doc is. Because It is well established that scanning and enabling OCR separates text from background and sharpens the text, you can't conclude anything.
And what makes you say it is a non ink signature?
How do you explain this document, which the white house released the same day as the PDF? http://www.wbur.org/files/2011/04/0427_obama-certificate.jpg