The barrel will be marked as to where it was made. Browning.com has sn data under cusotmer service. How it compares is a subjective call that only you can make after handling other makes.
The markings on the receiver and barrel will tell.
Serial number on a Citori is under the breakdown lever on the receiver. It should also be stamped on the barrel where it locks up on the receiver.
Yes, several different models have gold plating.
These shotguns were made from 1940-1945.During this time frame the belgium factory that produced Browning shotguns was overrun by the Nazi forces of Germany,and used to make firearms for the Third Reich.
Browning Arms
You will need to supply the serial numbers to your shotguns to get the age of your browning shotguns correctly.
That cannot be answered without a more detailed description of the shotguns overall condition,to include the wood,barrel,and receiver.
Yes. The magnum was not introduced until 1967.
Contact Browning.
www.browning.com
If you have the money.....
All Browning B-2000 shotguns were Belgium manufacture but assembled in Portugal.