The year of manufacture is 1940. Chack at Barnes and Nobles for a book entitled Gun Blue Book Values. It should give you an idea although prices can change with firearms sometimes within a few months.
Please include the model number of your Winchester shotgun to get a correct answer to your question along with the serial number.
Receiver/barrel
Check the receiver and barrel
barrel, tang, receiver
20IN.
Check the receiver and barrel.
Check the receiver and barrel area.
Check the receiver and barrel
Check the receiver and barrel
on the bottom of the barrel and reciever.
Barrel and receiver are the most common place.
You have to provide. It will be on the receiver or barrel.