Hello, I'm trying to identify an open faced pocket watch that my spouse's great grandfather passed on. It's a Henry Birks and Sons, open faced silver pocket watch about 1 1/4" in diameter. When the back plate is opened and the movement exposed, it says it's Swiss, a 17 Jewel Birks Buckingham, Serial No. 1869302 and 0,9355 sterling silver. I have looked online trying to identify it further, but my knowledge is pretty limited. Can anyone point me to the correct resources? Thank you.