Based on the serial number and barrel address this should be a Browning Auto-5 shotgun. You can confirm this by verifying that the receiver has the characteristic "humpback" shape.
The model is the Standard Twelve, made in Belgium in 1965. It's more common cousin is the Light Twelve that weighed bout 10 oz less. It is chambered for 2 3/4" shells.
In 1965 the barrels were not numbered to match the receiver, so you may disregard the different number on the barrel.
The Auto-5 was designed by John Moses Browning and was in continuous production from 1903 to 1997 with two interruptions for WW1 and WW2. It is the first self successful self loading shotgun design and one of the most highly regarded shotguns ever produced. About 2.5 million were made in all. The design was also marketed to Remington and Savage who each made a version of this gun.
The value is highly dependent on condition but most guns of this model, unmodified and in good shootable shape sell for around $450 USD.
I have a couple.
Jeff