Superposed
With the serial number that you provided,your Browning superposed shotgun was made in Belguim for Browning in the year 1955.
Browning Superposed Shotgun
John Moses Browning. The Browning Superposed was the first practicle over, under shotgun
The Dictionary says: "to place above or upon something else, or one upon another." As in the case of the Browning shotgun, the Superposed model ws the first sucessful Over/Under shotgun ever made. Browning used the dictionary description to name the model "Superposed" because one barrel is apon another.
If it is a Superposed model 1951.
The 72S suffix to your serial number indicates that your Browning superposed shotgun was manufactured in the year 1972,by FN of Belguim for Browning.
Does not exist. However, there is a famous over/under shotgun made by Browning call the Superposed.
The name is Superposed. Find this book - Browning Superposed: John M. Browning's Last Legacy by Ned Schwing
1935
1950 Superposed.
It will be marked on the botton of the receiver.