@mprough, you can have OPC re-generate those customers and address-book records by cutting and pasting the following into the store's Tools->Install SQL Patches:
Code:
DELETE FROM configuration WHERE configuration_key IN ('CHECKOUT_ONE_GUEST_CUSTOMER_ID', 'CHECKOUT_ONE_GUEST_BILLTO_ADDRESS_BOOK_ID', 'CHECKOUT_ONE_GUEST_SENDTO_ADDRESS_BOOK_ID');
That will cause the OPC auto-installer to create those customer/address-book records on the next admin login or screen refresh.