The wording is a bit different, but it looks like it's the forerunner to the current Moetzes Gedolei HaTorah of the Agudas Yisroel. Reb Moshe Soloveitchik had passed away a few months earlier, in Shvat of that year, and his son was asked to join the newly formed Rabbinic body. I do not know how long he sat on the Moetzes, conventional wisdom u\likes to use WW2 or the creation of the State of Israel as the date that he switched from the Agudah to the Mizrachi. So it's not just the Chinuch Atzmai and Torah UMesorah dinners that they sat together... But maybe we can be "מלמד זכות" on RAK that he since he had just arrived to the States from the European inferno that he didn't want to rock the boat yet...
But I can dream, can't I?
