Go to Browning.com to date it. For the Grade, you will either have to provide a detailed description or get a book on Brownings.
Go to Browning's site, Support, Date Your Shotgun.
1977
No serial number = no way to answer.
2006
You must call Browning with the serial number to find out.
1951
It was made in 1981.
1928
Your browning shotgun was made in 1990.
your browning auto-5 shotgun was made in 1926.
You will have to call Browning.
The MW in your serial number indicates that the browning shotgun in question was made in the year 2004.