Yes, it is designed to be non-disruptive as long as everything is cabled correctly (I have discovered physical cabling errors the hard way, so don't repeat my mistakes! 🙂 ). Although I'm sure it would work without migrating the cluster LIFs, I have always followed the documentation and migrated them prior to downloading the STK and reloading the switch, and then migrating them back afterwards.
If you have access to Active IQ, there's a pretty sweet Cable Visualization tool that will show you all of your physical cabling connections. If not, viewing the MAC tables on the cluster switches and correlating the data there to ONTAP cluster interfaces would always work in a pinch too.