No, I don’t think anyone has been able to compute the number of games.
But, if it hasn’t been discovered, then where does the quoted number originate? In a respectable publication like the Dutch Go Magazine it must have been sourced from somewhere.
Before you think it, there’s many words that are the same in Dutch and English. Like, rat, plank, plant, lamp, hard, hand, water (somehow all examples I can think of contain the a as a main vowel).
And tic-tac-toe and and many other games, but in itself that does not preclude reading/calculating. So this was not a well thought-out argument by Kissinger IMO.