Sync iPad 2 before upgrade iOS

[khumash]

iTunes pops up a message and ask to sync iPad 2 before upgrade iOS to 4.3.3 due to there're purchased apps. After sync'ing, I only saw purchased apps in iTunes, not those free ones.

Does this mean, if I don't sync iPad 2 before upgrade, only purchased apps will be removed from my iPad 2?

 

[Max]

Nothing should be removed from your iPad during an upgrade. The backup up is only for...well, backup reasons just in case something would go wrong.
Free apps from the iTunes store should still be there.