Do you suppose they are tags for a F&G vessel? Maybe a commercial license?
Metal Registration Plates
The metal registration plates previously used to display the vessel registration
number are no longer being issued by the Department. However,
previously issued plates may continue to be used as long as there is one
plate on each side of the vessel and the plates are not damaged. Vessel
owners must adhere to the vessel registration number display requirements
when:
Found here.
http://www.dfg.ca.gov/licensing/commerc ... linfo.html2010-2011 CF Digest Information .pdf page 10.
Just a thought.