There's a list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
The Ithaca side by side 12 gauge serial 188650 was made in 1927.
1938-39
It was made around the year of 1939
1951 is my best estimate. On line records from Ithaca went away when they closed. Sorry-
Your model 37 was mfg. in 1972.
There's a list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
If this is an old side by side it would be a Baker model made in 1886. Serial numbers of Ithaca shotguns for that year were 2448 - 4101.
There's a list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
1904
1910
I would say that you have a Ithaca model flues double barrel shotgun that was made in the year 1923,with the serial number that you provided.
The lefever Nitro special was made by Ithaca Arms from 1921-1948.That being said i believe that yours was made in 1927.I do know that you can contact Ithaca arms and they will date your shotgun for you.