Condor,
As previously stated I see no sign of any London Proof marks on the Barrels.Another significant factor is that the " Wheat Sheaf "trade mark on barrels made by Sir J. Whitworth process are absent.[IE; buyers paid a significant premium for Whitworth barrels and expected to see evidence that they got what they paid for]. I believe the barrels are replacement made and fitted in Birmingham. This is most likely the reason that some enterprising gun maker did not at some time in the past, purchase the gun and convert it to ejectors; net result financial gain!
This said, the barrels should perform well,unfortunately the collector value is reduced because of the replacement barrels.
