Is a serial number required on classified correspondence?

A serial number is indeed required on classified correspondence in order to maintain proper tracking and accountability. Including a serial number allows for efficient organization and retrieval of classified documents, which is crucial for maintaining security and ensuring that sensitive information is handled appropriately. This practice also facilitates audits and can assist in the investigative processes if necessary. The use of serial numbers minimizes the risk of loss or unauthorized dissemination of classified information, thereby reinforcing the protocols established by the Marine Corps for handling such material.