Caveat Emptor,
Beware, I have seen rebarreled guns that have been done by first class craftsman (many of whom do the original barrels for Best makers as outworkers)and they have fitted the original rib.So how do you really know what you are buying.
If I was a wealthy American, I would leave the market alone and allow it to become depressed and let us poor Brits retain our heritage.
In any case, boys, you now have your RBL's.