500-5000 USD depending on specifics.
There is no way to tell from the serial number.
The Invector Choke system was first introduced in 1983 and only available on Citori, BPS, and BT-99 models. Fixed choke barrels were still available as well. Please note that the Citori Lightning model wasn't introduced until 1988. All Citori Lightning models in 12, 16, and 20ga. were only available with the invector choke system (and still are). 28ga Lightning Citori's were still fixed choke only.
You might find them in the Blue Book of Gun Values.
Mid 80's
http://www.browning.com/customerservice/qna/detail.asp?ID=100
Look on the rear left side of the barrel.F=Full,M=modified,IC=improved cylinder,C=cylinder etc.
On the choke tubes. It is marked by lines on the front edge of the choke. The more lines the more open the choke. 1 line is a full and goes from there. If it doesn't have tubes, on the inside of the receiver near the bbls.
No way to answer without knowing barrel length and gauge.
Made in 1987. Depending on condition, gauge, barrel length, choke; a few hundred to maybe a thousand
You would use a full,or extra full choke if using 00buck for hunting purposes.If for self protection thats up to you.
100-1000 USD or so
Look for the symbol on the barrel from the codes below '*' designates full choke (F). '*-' designates improved modified choke (IM). '**' designates modified choke (M). '**-' designates improved cylinder choke (IC). '**$' designates skeet (SK). '***' designates cylinder bore (CYL).