I suspect you'd absolutely want to burn in before launch, maybe even including simulating some mechanical stress to "shake out" more issues, but it is a valid question how much burn in is worth doing before and after launch.
>>vidarh+(OP)
Vibration testing is a completely standard part of space payload pre-flight testing. You would absolutely want to vibe-test (no, not that kind) at both a component level and fully integrated before launch.