1971
serial #
Date of Mfg. is 1947
1951
1906
The serial number indicates Ithaca manufactured your Model 37 in 1956.
1950
1947
NID with serial # 446018 was made in 1927
I thought that would be in the end of the serial range of Ithaca but 1944.
There's a list of serial numbers by year at http://ithacagunrepair.com/page5/page23/
http://www.diamondgunsmithing.com/page5/page23/index.html
"Ithaca Featherlight Repeaters" by Walter Claude Snyder