No, the modified copy included the same certificate page simply because it was a modified copy of the PDF with the certificate page. There's no actual way I've determined to verify the signed checksum field.
Ah, so the 'signed checksum' field isn't actually the checksum of the signed document? How odd . . . but yeah, now that I think about it, they couldn't know the hash of a document before they generate it, but they would need to in order to include it in the document, hence an impossible cycle; they must have overlooked that . . .