the second pic brought up some questions in my mind:
1. are they replicas?
2. the left one in the second pic has Kahokia written on it, did it come from the museum gift shop?
3. they are from different places, but the drilling on them seems to be exactly the same. i noticed the drill holes don't seem to be beveled at all, and some of the drill holes have heat halos, common in shell that was drilled with a modern drill bit. which would be par for the course for replicas.