Daryl ,in my opinion based on the British market and past experience ,the value of a gun with barrels by "an other " irrespective of whom that is will reduce the value of a gun compared to the value it has with original barrels .
This is a strange state of affairs considering a good set of replacement barrels is better than a worn set of originals . It has there for been my experience that a gun such as the Woodward you use as an example with well sleeved barrels would not be worth much less than it is now.
New barrels by maker will significantly increase a guns value , but it will also cost you an awful lot of money so the gun has to be good to warrant the expenditure . I have heard of a pair of woodward's that were rebarreled by Purdey ,who own the Woodward name ,but they signed the barres as being by Purdey ,in effect lowering the potential value .I wonder if Purdey had been selling them would it have been different .
Bottom line is that it comes down to cost ,what you want to spend and what the realistic finished value will be .
An example will be [say a Beesley] sidelock value with good original barrels 6500 .Barreled by another 5000/ 5250 Sleeved 4500 plus . Same gun with scrap barrels 1000 plus in an auction on a good day.
If you want to have it done today The cost of rebarreling would be the over all value of the gun ,sleeving will cost around 1500.
