FIRST is there a letter code above the numbers?
http://www.browning.com/customerservice/dategun/detail.asp?id=13Is yours marked
BROWNING AUTOMATIC ARMS CO. OGDEN UTAH-U.S.A
First 10,000 shipped to U.S. Marked with "BROWNING AUTOMATIC ARMS CO. OGDEN UTAH-U.S.A." Very few serial number records remain.
Pictures would be most helpful, and you are sure you have a Browning and not an FN,
My old 16 gauge is

Thanks
Mike
p.s. read more here
http://www.16ga.com/forum/viewtopic.php?t=12350&highlight=dates+manufacture