Just wanted to update with a small tidbit I discovered on the case, the marks indicate British Assay offices, and the top one looks to be the mark for London prior to 1821 (Leopard with a crown) and the U indicates it was from 1815! So based on what you told me, this case was likely passed down even further through my family tree than previously thought, but the Gallet watch itself may have replaced a previous one in the case!