Your Ithaca model XL-900 which was made between 1973-1978,will range in price between 150-245 dollars for a example showing between 60%-95% of its original finish,and in good operating condition.
Its an Ithaca Flues model made in 1921
It sounds as if you have a Ithaca Crass model shotgun,that was produced in the year 1903 by your serial number.
Its an Ithaca Flues model made in 1921
Need to know model
1951 Model 37
You vave an Ithaca sxs Flues model made in 1911
It sounds to me that you have a Ithaca Flues model double barrel shotgun.With the serial number that you provided,your shotgun was made by Ithaca in 1917.
A model 37 with the serial # 10464 was produced in 1939.
You have a Lewis or NIG model, built in 1903.
Made in 1949
Made in 1968
By your description,it sounds as if you have a Ithaca model Flues double barrel shotgun that with that serial number was produced in the year 1914.