I seem to remember that he did take a polygraph for Orly when he submitted the Kenyan BC to the court. I know for sure he signed a declaration attesting to the provenance of the document which was also submitted to the court. Of course the case got no where so none of that came under legal scrutiny.
If he passed a compprehensive polygraph given by a first class operator that’s pretty good evidence on his side,not fool proof but significant.