The Redhawk issue had to do with a lubricant that was being used on the barrel threads during assembly. By all accounts, this issue was corrected once discovered and has not been a problem since. SP101s were not in production during that timeframe, so this is unlikely to be a related issue.
This issue with the SP101 sounds like a freak occurrence. A defective barrel made it through the quality checks and was found by the owner...
This article briefly mentions the Redhawk issue.
http://www.sixguns.com/range/454_super_redhawk.htm