There are many different models of Browning shotguns that were made in Belgium by the Fabrique Nationale manufacturing plant in Liege/Herstal. The oldest of which is the Auto-5 Automatic Shotgun which began in 1903. Some Superposed shotguns are still made there.
Your browning auto-5 shotgun was made by FN of belguim for browning in 1957.
Japan, Portugal and Belgium
Your belguim made browning auto-5 standard weight shotgun was made in 1962.
Your Browning auto-5 shotgun with the prefix of 70s to the serial number identifies that your shotgun was made in Belgium for Browning in the year 1970.
The barrel will be marked "Made in Belgium"
It will be marked on the receiver/barrel.
By the serial number.
You will have to call Browning with the sn to find out.
You did not provide a serial number. You will have to call Browning.
If your browning 16ga shotgun is a auto-5 then it was made by FN of belguim for browning in 1927.
Your sweet sixteen browning auto-5 shotgun was made by FN for browning in 1963.