We're definitely in the period where there are a lot of watches older than 100 years. Here is mine, a circa 1917 trench in a gold-filled Canadian-made case, color of which appears to be 9K-filled. A David Boettcher strap, with a matching 9K gold buckle.
Rolex, date letter 1915. Dial not marked (as with the case of many Rolex of the time that I have seen), but the Rebberg movement is marked Rolex. Sterling silver case trade marked W & D (Wilsdorf & Davis).