I am currently reviewing contractor data submittals that are marked "Copyright" - apparently such marking is OK (CLE068 says nothing about this) even though it restricts copying, derivative work, or displaying the work.
I don't see that you have actually asked a question. However, if it is your contention that marking contractor submittals with a copyright legend serves to prevent the Navy from using the submittals, then your contention is too simplistic. The CLE 068 serves merely as an introduction to a much more nuanced area of intellectual property rights and is not a substitute for researching the governing regulations.
While FAR Part 27
sets forth the general requirements for Patents, Data, and Copyrights, the DoD uses the guidance in DFARS subparts 22.71
instead. Those parts are too dense and lengthy to discuss in this setting. The Department of the Navy Office of the General Counsel is renowned for its intellectual property expertise. Likewise, lower echelon offices provide excellent support to Navy clients. For instance, the Navy Air Warfare Center has a most informative webpage. You can find it here: http://www.navair.navy.mil/nawcwd/command/counsel/IntellectualLaw.html
You should read those DFARS provisions and clauses which are relevant to your review of the submittals and discuss your concerns with your supervisior and servicing legal office.