I, too, was at the Roosevelt Stadium show on Jerry's 31st birthday in 1973. It was a few days following the Watkins Glen show with the Dead, The Band, and the Allman Brothers. (600,00 in attendance, bigger than Woodstock!) The Band opened at Roosevelt Stadium and it was the final appearance of Alligator. Great Dark Star as I recall. Twelve days later, I moved to California.
Bill, tgo