Best to get help from a gunsmith.
About 1921.
how do you disassemble a colt woodsman
mfg date about 1921. value depends on overall condition................
A Colt woodsman .22 with that serial number was made in 1930.
colt woodsman 22 automatic 851119 made about 1934
You will have to call Colt with the sn to find out.
From Colt. Follow the link below, and scroll down to find your version of the Colt Woodsman. You can download the manual as a PDF file.
That particular Woodsman was made in mid-1950.
Proofhouse.com has Colt sn data.
If it is a Colt woodsman or match target,sround 1949.
Colt woodsman 22, about $500.
Since you did not provide the serial number, you will have to call Colt to find out.