Missing model engravings on the closing cap or end piece are no compelling indication of counterfeit — collectors know originals without corresponding lettering, presumably from Monday-production. Steel nibs were not exclusively fitted in the 136 during the war; here too there are legitimate variations. Decisive are overall proportions, ink window, piston mechanism and material; in case of doubt an experienced restorer like the named specialist should give an assessment. A new cork is often due on old 136s and is unproblematically obtainable via specialists.