"Only six digit" isn't that old, as most of the ones out there were produced with 6 digit numbers, and they got up to the low 7 digits. Here's more info:
http://proofhouse.com/browning/a5.htm
So the oldest year the gun could've been made in is 1930.
With the serial number that you have provided,your Browning sweet-sixteen auto-5 shotgun was made in the year 1952.
If your Browning auto-5 shotgun is in 12 gauge,then it was made in the first year of production which was 1903.If you have a 16 gauge auto-5 shotgun,then it was made in the first year of production which was 1909.
your browning auto-5 shotgun was made in 1926 by FN of belguim for browning,with the serial number you provided.
You will have to call Browning with the serial number to find out.
your browning auto-5 was made in 1927.
Your browning auto-5 wa made by FN of belguim for browning in 1931.
You will have to call Browning with the serial number.
With the serial number that you provided,your browning auto-5 shotgun was made by FN of belguim for browning in 1907.
Your browning auto-5 magnum shotgun was made by FN of belguim for browning in 1965.
your browning model auto-5 shotgun was made in 1924.
Your browning auto-5 shotgun was made by FN of belguim for browning in 1957.
You will have to call Browning with the serial number to find out.