This one appears to be the first version of the Beau Brummell "C". 10K Yellow gold filled with a 21J movement and diamonds at 12, 3 and 9 mounted in arch topped triangular mounts. Runs and keeps time as received. Mounted on a black suede replacement band by me. Appears to be the first "C" for the database in this configuration.
1958 Beau Brummell "C" per the 1958 Linebook.