I agree, sifting fact from fiction is what it’s all about...but that paragraph in ‘Dreams’ includes two items; the newspaper article which has been found, in which is shown that the kenyan was interviewed in June 1962, where he is quoted as saying he had not been back to Kenya for seven years ( Ayres slipped up, he should have left that out)...
So I am inclined to believe that he might also have found a birth certificate at the same time...
Do you remember about what year it was that he found the article and certificate?