The answer is no, drift at one generation is always around the allele frequency of the previous generation only; and allele frequencies in more ancient generations are totally irrelevant. THERE IS NO TENDENCY TO RETURN TO ANCESTRAL ALLELE FREQUENCIES.Genetic Drift: The Role of Finite Population Size.
But the point the biologists want to make is that that isn't really what is going on at all. We don't need 120 changes [in hemoglobin -- VR] one after the other. We know perfectly well of 12 changes which exist in the human population at the present time. There are probably many more which we haven't detected, because they have such slight physiological effects...[so] there [may be] 20 different amino acid sequences in human hemoglobins in the world population at present, all being processed simultaneously...Are the Odds Against the Origin of Life Too Great to Accept?