"I'm afraid that in the past I have contributed to the logical, but incorrect, assumption that the PF and other oval markings on the nibs had to do with manufacture.
Herr Ehlers informed me that they are customs markings for the various pre-EU European nations most notably the Swiss (god bless them)."
"I'm afraid that in the past I have contributed to the logical, but incorrect, assumption that the PF and other oval markings on the nibs had to do with manuf ...