Your Browning sweet sixteen shotgun was made by FN of belguim for Browning in the year 1951.
1952.
Your browning sweet sixteen shotgun was made by FN of belguim for browning in 1961.
Your browning sweet sixteen shotgun with a 5s prefix dates your shotgun to the year 1965.
Your browning sweet sixteen shotgun was made by FN for browning in 1928.
A5
Browning.
That is not a Sweet Sixteen serial number.
Semiautomatic shotgun
The serial number prefix 1S was assigned to the browning sweet sixteen model of the auto-5 shotgun in the year 1961,So yes you have a Browning sweet sixteen shotgun.
With the serial number that you provided,your browning sweet sixteen shotgun was made by FN of belguim for browning in 1928.
Both the sweet sixteen model and the regular production semi auto shotguns were Browning auto-5 shotgun models.The regular Browning auto-5 shotgun had engraving on the receivers just like the sweet-sixteen.