Since posting my last message, as recommended, I have obtained an extract from the Patek archives which confirms my watch's authenticity and states that it is a 1967 model 3537 18k white gold 23-300 manual winding Patek. However, I am still unable to ascertain why the inscription on the face differs from anything else I have seen. Does anyone have any idea how I can find out why it has Patek Philippe & Co Ginebra, when my jeweler feels that it has not been tampered with and the type of dial is not mentioned on the archive extract?