Basically impossible to value with just the serial number.
Your Browning lightning superposed shotgun was made in the year 1968 with the serial number that you have provided.
Your Browning superposed,over under 20 gauge shotgun was made in the year 1951;with the serial number that you have provided.
Most likely a Superposed.
You will have to contact Browning.
Browning can tell you how it left the factory, and the gun can be dated by serial number.
If it is a Browning Superposed 12 gauge it was made in 1959.
HI, the gun was manufactured in 1969, Carl
Browning.com has a sn function under customer service.
100-1000 USD or more.
The Superposed is an over/under. Check the BPS section on Browning's site for pump shotguns.
Browning.com has a sn function listed under customer service.
You will either have to call Browning and give them the serial number, or you can look it up on their web site or Matt Eastman's book or the blue book of gun values