The Puppet tool will be helpful even if all the servers are unique. All servers are unique in some way or another, but they are not unique. For instance, even if the IP addresses or the hostname might be different, generally servers run on relatively standard Operating System (OS).
In case a server is unique, Puppet can be useful as it will help in terms of uniqueness as well as consistency. It will help to express the expected consistency, and it can allow special provisions so that the server’s uniqueness can be handled.