If the device was documented as part of an initial full network documentation process, the entries in the DHCP and DNS databases need to be checked. If the entry is missing, wrong, or incomplete, it must be corrected in the DHCP and DNS databases. If the entries are correct, then no changes are needed to those servers. The device can simply start using the servers. The only synchronization requirement is that the DHCP and DNS servers be updated before the device, so these can be scheduled as convenient.
If the device is going to be dynamically assigned an IP address by the DHCP server, then the DNS server database should be updated to reflect that DDNS is now going to be used for this device. This update should not be made ahead of time. It should be made when the device is updated.