There was no compulsory Sunday morning chapel requirement when I was an undergraduate in 1963. As as I recall, the requirement was that as freshmen only, we were to attend a certain number of religious services (10, I think). I did my attendance at Hillel, which was located at the small campus theater. I certainly never attended a religious service in the University Chapel.
Editor’s note: According to the PAW archives, compulsory chapel was not completely eliminated until June 1964, and religious services for Jewish students, like the ones mentioned above, began as early as the 1910s.