It happens. Does not add any real value.
Impossible to answer without knowing the caliber.
The caliber will be marked on the Barrel, the year made is 1983
yes
A browning safari grade rifle in a standard caliber,and the condition you describe is valued at 995-1,100 dollars.
Impossible to answer without a detailed description of ALL markings, caliber/gauge, barrel length, sights, stock, etc
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.
It may be different depending on the year and the caliber, but recent catalogs show that the few A-Bolts witha 24" barrel have a rate of twist at 1-10"
you will need to call Browning.Browning chose a 1"in 14"twist rate for all rifles chambered in 22-250 caliber.
Browning.com has sn data on their web site under customer service.
Need to know the finsih, condition, accessories, box, papers, etc..
These are mostly proofing marks and caliber and barrel length markings. There are books on the market that define Belgian proof marks
Well, it depends on what you mean. The caliber is "determined" at time of production based on whatever caliber the manufacturer wants it to be. The caliber can be determined later by looking on the barrel. The caliber will almost always be stamped somewhere on the barrel.