Rule 1410 Nothing in this article shall be construed to limit the means by which a writing may be authenticated or proved.

This rule says that the other rules in this section of the evidence code do not cover every possible way to prove a document is real.

If you have a document you want to use in court, you are not stuck with only the methods listed in these rules. You can use other methods to show the document is genuine, as long as the court accepts them.