No way to answer without the serial number. Recommend you visit the Browning website, they have sn data posted.
what is the manufacture dateof springfield serial# 1226813
What you have listed is not the serial number. It should have three letters in front of it.
fn a5
81 junior
1973
1950
1931
YOu must call Browning.
1950.
1928
Browning.com has serial number data under customer service.
Your shotgun was made in 1947 with the serial number you provided.