It's possible that there isn't one - serial numbers on firearms didn't become mandatory until 1968.
your Winchester model 1906 serial#239054 was made in 1911.
With the serial number that you provided,your Winchester model 1906 .22cal rifle was made in the year 1912.
With the serial number that you have provided,your Winchester model 1906 was made in the year 1909.
With the serial number that you have supplied,your Winchester model 1906 was made in the year 1911.
your model 1906 Winchester was made in the first yrs of production 1905-1906.
oldguns.net
With the serial number that you have provided.Your winchester model 1906 was produced in the year 1914.
1906
1906
1910
1906.
With the serial number that you have provided,your Winchester model 1906 .22cal rifle was made in the year 1908.