I don't know why you were taught specifically about an overspeed C/B. In 15+ years I've never had an "erroneous" overspeed warning in any 747 model.
In our early 744 days, one airplane had repeated, random, erroneous aural warnings for several weeks. We eventually pulled an Aural Warning C/B (don't have a panel depiction to identify/locate it), but it silenced ALL aural warnings, including altitude alerts.