a. Prior service members. Coast Guard personnel who previously served in
another branch of the Armed Forces and received personal, good conduct,
unit, campaign, and/or service awards listed in enclosure (22) are authorized
to wear them on the Coast Guard uniform with the exception of
marksmanship medals and ribbons.
So basically everything except postol and rifle, http://www.uscg.mil/directives/cim/...50_25D.pdf