I was hoping someone might be able to help me out with a question I have about a Caran d'Arche pen. I love pens and other stationery and I have always wanted a Caran d'Arche pen but they are rather expensive so I have never bought one. A few weeks ago I went to an estate sale and bought a really nice looking one for around $12. Not a bad price I thought and the pen looked good and worked but the ink cartridge was in need of replacing. The pen is old, probably 1950's or 1960's but I like to know more about it. It is a ball point pen and not a fountain pen and it appears to be gold plated but I'm not for sure (I'd like to know). I contacted Caran d'Arche and gave them the number that was engraved on the inside of the barrel (you can only see it when you take the pen apart to put a new cartridge in). The number looks like a serial number or possibly just a manufacturer's number of some kind but I thought that if I gave them the number they would be able to tell me when it was made and what kind of pen it is (and what kind of metal it is and the refill it takes). I wasn't able to find out anything from the company after exchanging a few emails with them, which seems odd that they can't simply look up the number. I'm guessing the number has the date of manufacture in it as well but that is only a guess. The number is six digits long. For example 161759. I was wondering if, for example, that the number 1 was the factory, 617 was the number of pens made up to that point and 59 was for 1959. Of course I could be way off but I'd love for someone to explain the number to me or point me to a site where I can reference my number to find out more information on it. If anyone has any suggestions I love to hear them. Thanks in advance.