Yes. Brokerage statements will not always report the cost basis and/or sales category, even if the information is available right on the 1099-B. The IRS is receiving the 1099-B information from the broker, but is relying on you to report the correct cost basis and category.
For unreported cost basis:
Make a reasonable estimate, based on old trade confirmations or historical prices from a source such as www.finance.yahoo.com
For unreported sales category:
If you held the security less than one year, use code B (short-term, noncovered)
If you held the security more than one year, use code E (long-term, noncovered)
