The dent issue is a little trickier than just difficulty in raising the dents. Once the 2 layers of metal are separated, one is liable to get an electrolytic reaction, called cavity corrosion I think, which in time could mean the rotting away of the original iron in that vicinity. This is unproven as yet but I have heard it said by a metallurgist that this is a very real possibility.
2nd problem is that arguably the ribs can not be relaid after having lined the barrels as the heat of the soldering is over the denature temp of the glue that Teague uses.
Moral of all of this is precisely as Small Bore says above, its a good repair but a new set of barrels it is not.
Also, get your ribs relaid before you get the barrels lined.
