PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX dc:   <http://purl.org/dc/elements/1.1/>
SELECT ?name ?givenName
 WHERE { { ?x foaf:name  ?name } UNION { ?x foaf:givenName ?givenName; dc:created ?created } .
         FILTER ( bound(?name) || ?created < "2005-01-01T00:00:00Z" ) }