Depends on condition, from a $100 parts gun to a $1500+ new in the box.
Any very good 12c is worth $500-600, jumping quickly nearer to mint.
Oh and 1909 is the patent date, other then made after 1909 is has nothing to do with the date of manufacture. For manufacture date if it's after 1920 it will be date code stamped on the barrel see related links for information on the Remington Society of America, if there's no date code need serial to date it.
The Remington model 12C slide action 22cal. was produced from 1909-1936.
Depending on condition the blue book value is between $250 and $800
yes with the serial and a VERY good description on condition.
1911
1914
Early 1920.
Manufactured 1914
1919
1920
Late 1911
1909 to 1936 with a serial can date it, also 1921 and later are date code stamped on the barrel.
1915