All registered documents are public documents?

Yes, the registering officer must allow any person to inspect and obtain certfied copies as public documents.

All registered documents are public documents. But there are exception to this, A certified copy of a WILL, if it is registered, can only be obtained by the concern person as far as i have seen. 

Some one should correct me if I am mistaken.

1.Registered document is a private document.

2.The copy of such document appearing in the books of Registrar is a public record.

3. Any one can get such certified copies as recorded in the books of sub registrar.