As far as the documentation regarding projects goes, all of it is handled in accordance with the government security policy. It's either classified or it's unclassified.
If it's classified, then it's part of documentation in support of a project. It is treated accordingly. The contractor has to have the appropriate security clearances. They're all verified and they're handled accordingly. Whether they're numbered documents and not copyable, whether the contractor has the right storage facilities on-site, whether the contractor is only accessing classified documentation or whether he is required to store it—all these issues are treated as if the contractor were a government employee with the appropriate security clearances.
If it's unclassified documentation, it's treated as unclassified documentation and is controlled accordingly, which means there are very few controls over it.