Go to gunbroker.com and take a look at the 100 or so Browning A-5 semi automatic shotguns that are offered. Prices start ( in Aug 2007) at 200 and go to $1000 for a Belgiumj A-5 new in the box. Rebluing will reduce the value of your gun by 50% at least and if the general condition of the gun, dents, dings, rust, are present the gun is further devalued. Engraving enhances the value of a gun especially if it is custom factory engraving. Good luck
Requires professional appraisal
You need to identify the make and model of the shotgun. Dozens of different makes of guns show a browning patent on the barrel. Recheck and re-ask the question - Thank you
Depends on who engraved it, the pattern, the wood, barrel length, accessories, box, papers, etc.. A few thousand USD or so
Although both are interchangeable, a true Sweet 16 barrel will have three holes drilled through the barrel band. This was one of the ways Browning lightened the barrel. The rib will also be a smidge thinner than on a regular barrel.
You will have to ask Browning.
You need a trained Browning gunsmith
It will be marked on the barrel. The barrel is marked "Made in Portugal".
It is possible
Marked on the barrel.
Break open the action and it should be engraved on the metal that is normally unseen when the action is close, that or it should be on the barrel. If the chokes are removable then it should be engraved on those as well.
The Browning web site has a search function that will assist you.
You must call Browning with the serial number.
Try gunbroker.com in the barrel section.
The Browning 2007 Product Catalog states that the A-Boltchambered for 25WSSM with a 22" barrel has a 1 in 10" rate of twist.
Leave this to a gunsmith