I have a Tiffany pocket watch in 18k gold. It runs well and is in great condition. It has an open face, and a double cover on the back. It also has a stopwatch feature. The face and movement are both marked Tiffany and Co.. The case has British gold hallmarks that include a stylized "O" but the case itself is not marked Tiffany. Both the movement and the case are marked with serial number 6220. Can anyone tell me about this pocket watch? When was it made? Is it at all unusual for a Tiffany pocket watch? Who made the movement? Any info about this pocket watch would be appreciated? Thanks in advance.