So holds the Arizona Supreme Court; the Washington Court of Appeals held the same a year ago. The decision applies to whatever metadata is stored with the document, including creation, modification, and access dates, the identities of the creating, modifying, and accessing users, and so on (at least unless some exception to the public records act applies).
The decision does not require that the computer systems maintain any metadata; it only requires the disclosure of whatever metadata is present. “[W]hen a public entity maintains a public record in an electronic format, the electronic version of the record, including any embedded metadata, is subject to disclosure under our public records law.”
Thanks to How Appealing for the pointer.