Metallurgically it would be interesting to see what they claimed. The materials tensile strengths should not have varied with modern steels. A major issue with the form 4 work and welding repairs to bring the boiler up to the new code is the materials characterization of the materials used in the boiler. While I would still recomend testing in today's engineering envioronment, it would be interesting to see if any changes have occured due the passage of time from a materials characterization standpoint.
Robby