As the barrels will have been made of mild/low carbon steel, the heat can have damaged only the solder and/or caused rusting. Mild steel is not subject to heat hardening; likewise, it is not subject to heat "softening." So, if there is not too much rusting (esp. in the form of pitting) and you can economically justify relaying the ribs, I'd say they could be repaired from a metalurgical viewpoint.

DDA