This is a story my father told me as having happened while he was there at the dinner, which would have been in 1966, 67 or 68. I'm not sure if my memory of a family story is reliable evidence, but I am passing it on in case it's helpful. I support your quest for these facts wholeheartedly.

We had a geography teacher who could be extremely easily derailed into talking about any interesting thing you saw on TV that week, we thought we were geniuses distracting him from his lesson plan into conversations about space or whatever but he was stealth-educating us, the BASTARD