BLue Book of Gun values is a place to start
what is the question?
50-150 USD or so
This is an Auto-5 Shotgun
The Name Fabrique Nationale D'armrmes de Guerre is the name of a gun maker located in Herstal,Belgium.They have made firearms for Browning since 1909.The firm also makes many firearms for themselves also with the name you have used marked on the side of their firearms.
fabrique nationale
Go to http://www.browning.com/customerservice/dategun/index.asp
Fabrique Nationale
Colt. Licences to manufacture it were also granted to Fabrique Nationale, Chartered Industries of Singapore, and Daewoo Heavy Industries.
No published sn data
Without knowing the rest of the markings, my best guess would be late WWII.
This is the Belgian firearms company Fabrique Nationale
Fabrique Nationale d'Herstal
fabrique nationale & Taurus
Fabrique Nationale (the name of the company) arms of war, Herstal, Belguim (place of manufacture. Brownings patent filed.
Have you tried their web site?
This model was created in the world war era around 1927. The cost of purchase as at that time was $300.