SEC states it themselves on their website that not alll documents filed with the comission by companies will be available.
Not all documents filed with the Commission by public companies will be available on EDGAR. Companies were phased in to EDGAR filing over a three-year period, ending May 6, 1996. As of that date, all public domestic companies were required to make their filings on EDGAR, except for filings made in paper because of a hardship exemption. Third-party filings with respect to these companies, such as tender offers and Schedules 13D, are also filed on EDGAR.