Mechanically, none. One just weighs less than the other.
Impossible to answer without a serial number.
It shouldn't say light twelve on the barrel, but on the receiver. Light twelve means that the gun is a light weight version of the standard Auto5 shotgun.
Which guage?
Your serial number indicates that you have a Browning standard auto-5 shotgun in 16 gauge that was made in the year 1961.
The serial number L52789 indicates that you have a Browning light weight model,auto-5 shotgun which was made in the year 1955.
No serial number provided
Sounds like you have an American made Browning. These were made by Remington under contract for Browning from 1940-49 If this is correct, the serial number is on the left side of the receiver. It is not however a sweet 16, but a standard weight American Auto5. this serial number represents a gun made in 1945. auto5man
1938, Belgium
You need the services of a gunsmith
it was made in 1961
This is a 16ga 2 3/4 Belgian made auto5 made in 1949. It could be a Sweet 16 which is the lightweight version or a Standard weight gun. See the link below on values. What other information would you like to know?
Go to Browning.com and you can download a manual