You can download a manual or request one from Browning. IMHO, you need the services of a good gunsmith.
100-1000 USD depending on specifics.
50-575 usd
Impossible to answer without a detalied description of all markings and features.
No
AFAIK, Browning never made a 1 gauge shotgun.
Depending on condition $300-$450
You will have to call Browning to find out.
You will have to call Browning to find out.
10-1000 USD or more depending on exactly what you have.
10-10000 USD depending on specifics
Your best bet is to go to Browning's web site and request a manual. You don't mention if it is a over/under, side by side, pump or semi-auto.
You will have to call Browning with the serial number.