A document is filed when it is received by the Commissioner. The Commissioner shall keep a register of every application for registration, every notice filing, and every registration statement which is or has ever been effective under this title and every denial, suspension, or revocation order which is entered under this title. The register shall be open for public inspection. The information contained in or filed with any registration statement, application, notice filing, or report may be made available to the public under the rules which the Commissioner prescribes. On request and at the reasonable charges which he prescribes, the Commissioner shall furnish to any person photostatic or other copies, certified under his seal of office if requested, of any entry in the register or any document which is a matter of public record. In any proceeding or prosecution under this title, any copy so certified is prima facie evidence of the contents of the entry or document certified. The Commissioner may honor requests from interested persons for interpretative opinions. The fee for issuance of an interpretative opinion is $100.