Copyright Registration is not required for claiming copyright. Copyright comes into existence as soon as the work is penned down and registration of copyright is optional. If you expect a dispute, a registration may come in handy as a proof, but it is not mandatory. The protection under relevant law is available irrespective of registration of copyright.
So, your decision to register for copyright should be based on whether you expect a dispute and whether you would be willing to spend time and money on the same.