Impossible to answer without the serial number
Your serial number indicates that your Ithaca shotgun was made in the year 1920.
1976
1924
Impossible to answer without the serial number
1905
about 1925
It sounds as if you have a Ithaca Crass model shotgun,that was produced in the year 1903 by your serial number.
With the serial number that you provided,your Ithaca double barrel shotgun with the damascus barrels was produced in the year 1900.
You vave an Ithaca sxs Flues model made in 1911
Ithaca began manufacturing shotguns and rifles in 1880, often using expired Remington patents.
You may contact Ithaca arms and they will date your shotgun for you.
1938-39