Around $1200-$1500 in excellent condition.
Between 1200 and 1750 US
They tell you what the barrel(s) is/are choked. One-full, Two=Modified, Three = Cylinder.
GO TO BROWNING WEBSITE AND GET CHOKE SPECIFICATIONS FOR DIFFERENT CHOKES AND MIKE END OF BARRELL
Yes, there are several sources on the intermet where you can find barrels. Japanese barrels are more recent, but even so, original Belgium barrels can be found at places like Gunbroker.com and Midwest supply.
300-500 USD
No
No
800-1000 usd
The steel is stronger, but that doesnt nescesarilly mean its better
Yes, all Browning Invector and invector plus barrels can shoot steel shot.
No, they are not.