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).
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.