Well, first of all the serial number given is for a model 37 and not the model 51. All model 51s serial number begin with 5100. Since your begins with 37 would you not believe that it is a model 37. Your model 37 was mfg circa 1975.
1976 is the year
1973 - Ithaca Model 37 Featherlight
The serial number indicates your gun was manufactured in 1966.
Made in 1972. Probably worth about $350.
Depends on the model and condition. An Ithaca Mdl 37 Featherlight in 16 g in excellent condition is $500-$600 at retail.
Your Model 37 was mfg. in 1954. The -4 indicates full choke.
1963. Check out the full list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
I have seen them selling for between 250-325 dollars depending on condition and a good bore.
Your Model 37 was mfg. in 1975.
What is the condition of the gun and the barrel length?
100-400 USD
well i wanted to know what my 16 gauge featherlight Ithaca how old it was and how much it was worth i called Ithaca arms gun co. out of Ohio because they are no longer made in Ithaca New York so that's your best bet