No
The "rate of twist on rifling" is caliber specific. To give you an answer we would need to know which cartridge the rifle is chambered for.
A browning safari grade rifle in a standard caliber,and the condition you describe is valued at 995-1,100 dollars.
It will have to be custom made.
Yes
Without a better description, 300-900
The Browning 2007 Product Catalog states that the A-Boltchambered for 25WSSM with a 22" barrel has a 1 in 10" rate of twist.
20 inch.............
If it is a Browning Superposed 12 gauge it was made in 1959.
You will have to contact Browning to find out. If you are referring to the run of Browning model 71's that were made between the mid to late 80's and early 90's, there were a total of 14,000 made. 4,000 Standard Rifles with a 24 inch barrel. 4,000 Standard Carbines with a 20 inch barrel. 3,000 High Grade (Deluxe) Rifles with a 24 inch barrel. 3,000 High Grade (Deluxe) Carbines with a 20 inch barrel.
Requires professional appraisal
Any rifle with an 8.5 inch barrel is a class 3 weapon.
100-10000 USD depending on specifics