No, not to say it is new technology, just to avoid the hassle of resoldering. Some things just do not sit right with me and all that rigmarole with clamps, torches and solder is one of them. As if that is not enough every rib resolder means rebluing. I feel sorry for guns that undergo this brutality.
Darnes with their single top rib are by no means modern. I have yet to see such a Darne with rust between the barrels. They also balance superbly without the weight of the bottom rib. For those that insist on seeing a bottom rib, the other French great, the Ideal, had an "I" secton rib that fit between the barrels. In short there were old solutions to the ribs. I wonder what we would think of the "I" rib if it had been used on "best English" as opposed to "best French".