Some makers have the info on their web site.
We cannot tell from a serial number alone. You might check with Savage Firearms customer service (They own the Stevens brand)
You will need the model and type of gun- and check with Colt customer service.
Varies by manufacturer. Some manufacturers print the manufacture date on the rifle (this tends to be more common on military firearms). Others, you may have to audit the serial number either against a published list (such as Ruger firearms), or you may have to call the company and have them check their records against your serial number.
this website will give you access to dates of manufacture by serial number for most of Winchester firearms. http://oldguns.net/sn_php/winmods.htm The model 12 you ask about was made in 1930. Check it out.
Contact the manufacturer with the Serial Number, check at you local library for Gun digest, Blubook of Gun Values, Modern gun Values and ome times they will provide an age range for firearms based on serial number.
Check with local law enforcement. They can check the serial number against the NCIC data base for stolen firearms. This is a National database that is NOT available to the general public.
Most manufacturers of firearms keep detailed records of various models and their respective manufacture date. Check out the Colt firearms website as a starter
Check the Blue Book of Gun Values, Stanard Firearms Dicitionary or proofhouse.com 1903. Colt single action revolvers in 1903 started with serial number 238,000 and 1904 serial numbers started at 250,000.
Only if serial number data is available
Read it on the receiver <><><> If by "run", you mean check it against a database of stolen firearms, THAT database is available only to law enforcement. You can ask local police to check for you- they will want to have the gun in hand when they do that, in the event that it IS stolen.
check the serial number.
Newer S&W revolvers have the model number stamped on the frame,above the serial number. The date of manufacture will be in one of the many reference books about S&W firearms. Check Amazon.com.