The scanned PAC (anyone know what PAC stands for?) chips have different edges. The pink has a serrated edge while the white is smooth, square edged. I assume that they were in use at the same. Why are the edges different? Same thing occurs with the "SS Rex", "Balinese Room", "Agua Caliente", "Chesterfield", and "Christiana". While I'm at it, I have a square edge and a rounded edge StageCoach chip.

My guess is that different edges provides an additional means of distinguishing the chips. The round and square Stagecoach chips may be because they were used in different clubs (has it been determined wether or not they are generic chips?)