I need help with this Seikosha Chronograph Pocket Watch. I found the same on the web but there is something that I cannot explain. Each of them has some writings and numbers on the back. Mine doesn't have it. But the case inside looks completely the same and has the same marks and that small writing SKS. What do you think about it? Does anybody have a watch like mine? Can you tell me something more about it? Here are some pictures I made.