Usually, no; the Source Release Date tracks when the vendor published the update (often used to meet SLA’s for patch timeline expectations), but correcting a false-positive or false-negative in the relevance doesn’t usually trigger an update to Source Release Date.
There are ways to get the true modification times for the Fixlets, but requires a Session Relevance query - it’s not exposed as a field in the user interface. I can work that out if you’d find it helpful?