Several film clips are seen and sound clips are heard of Judy Garland, who died June 22, 1969, just six days before the Stonewall Riots started on June 28, 1969.
The picket at Independence Hall was a yearly event called the Annual Reminder. It took place every July 4 from 1965 to 1969. The Stonewall riots began June 28, earlier in the summer than the Annual Reminder.
The sip-in depicted took place in 1966, not 1969. It was not the Stonewall Inn that refused service, but a bar called Julius (which is shown as the sip-in's first stop in the film).