Only the maker knows.
A lot!. Starting with the least expensive, Grade 1, Pigeon, Diana and Midas. After WWII, Grade 1 Grade II, Grade III, Grade IV, Grade V, Grade VI. In 1960 they started back with Gr 1, Then Pigeon, Pointer, Diana and Midas. Presentation grades were 1,2,3&4. Waterfowl limited edtions were Mallard, Pintail, Black Duck and Bicentennial.
Information is not in the public domain.
Not published in any reference.
Browning produced almost 3 million Auto-5s
If you go to the browning home page,they may be able to answer your question.
5
There are many different models of Browning shotguns that were made in Belgium by the Fabrique Nationale manufacturing plant in Liege/Herstal. The oldest of which is the Auto-5 Automatic Shotgun which began in 1903. Some Superposed shotguns are still made there.
Information is not easily avaialbe to the general public. A shareholder might know.
He didnt invent the shotgun, however he invented many different models of shotguns. auto5man
The browning superposed shotgun was first made in 1931.the serial number run began with the serial number 1 and ended with the serial number 2,000.
Information not in the public domain.