Passenger Side Lock Issue on 65 Dart

Hey all - This morning I went to unlock my passenger side door and the door stayed locked and the locking cylinder just spun around 360 (took a moment for me to figure out how to get my key out, too)!

Does anyone have any diagrams or any info about the locking cylinders on the early A's? I'll obviously have to take the door card off and see what happened, but I always like to do some research before I begin

Thanks