Examine with high power magnification.
In order to determine the age of Lefever shotgun, the serial number must be known. However, Lefever shotguns were only made and distributed between 1885-1916.
The model number is on the water table directly after the serial number, usually a letter ranging from A thru I with I the least fancy.
Open the action. It is stamped on the water table, which is the flat part of the frame where the barrels sit. sales@countrygunsmith.net
The Browning website has a page enabling you to find your shotgun's age, but you have to know the type of shotgun you own. Go to the page, then click on the type of shotgun it is - there are 15 types - and then reading the page for that gun's serial numbers. Look for the series of serial numbers that includes the one you are interested in: #48162.
Made in 1904. Value depends on grade and condition.
You can find these numbers in the manual that come with your gun. They are also present on the handle of the gun.
You will have to find a listing of all the serial numbers from the maker for the shotguns they made and go through them.
The Serial Numbers are along the Left Side of the Receiver just Above the Stock.
Serial numbers were not required before 1968. Check the barrel and receiver.
Made from 1964-81. No breakdown on numbers I can find.
Shotguns made in the US before 1968 were not required to have serial numbers. Would have to go with whatever markings are on the gun.
Serial numbers were not required on long arms before Jan 1, 1969. Most manufacturers did not assign serial numbers to small caliber rifles or utility shotguns.