Under $100.
Check the receiver and barrel.
Best left to a professional. Find a gunsmith
Check the barrel and receiver. Sn's were not required before 1968
I believe that is a model 311. I have the same double barrel.
between the stock and the barrel
Manufactured between 1886 and 1916.
The Stevens double barrel shotgun is worth $350 to $450 dollars. The value is determined by the gun's mechanical condition.
Check the barrel and receiver
The Stevens model 311 was discontinued in the year 1989.You would have to contact Savage/Stevens to get the actual age of your double barrel shotgun.
Try the receiver, barrel, forend
It will be marked on the receiver/barrel.
Check the receiver and barrel