This depends on a few different factors:
1. ePO will re-associate to the same LeafNode ID in the ePO database if the system connects using the same MAC address as the last communication and McAfee Agent does not have a GUID. If the MAC is different a new LeafNodeID will be created and thusly an entry in system tree will be generated.
2. If you enable MDE the Machine key re-use option the previous key will be reused to encrypt the system. If not the system will generate new keys. This option is found in Server Settings | Drive Encryption | Edit
3. If using MNE to manage Bitlocker, Bitlocker will generate new keys.
Note: ePO does not generate either recovery or machine keys for either Bitlocker or MDE; these keys are generated on the client system and uploaded ot ePO. If using machine key resuse, the key is stored on ePO from a previous generation and the system download the key and reuses it.