Odds are that all of the completed product had corroded leads, if the components came from the same load / were processed similarly.
... but the issue is NOT corroded leads. The issue is well soldered connections. * If the solder connections on these components on the completed product look perfect, then you should have no concernes about future failures. Convince yourself that this is true by sectioning and performing metalgraphic analysis on some of the questioned solder connections. * If the solder connections on these components on the completed product look like your solderability sample, then you should engage a failure analysis laboratory to help you understand the potential for and mechanisms of future failures.