Questions about updating iPod Touch 2G to iOS 4

My girlfriend's computer's hard drive was wiped recently. She transferred her music and apps back into iTunes with Sharepod. iTunes has a current backup of her iPod saved. All of her music and apps are in iTunes. She has lots of notes and voice memos that she cannot afford to lose. Should she be fine upgrading in iTunes without losing her app data, notes, memos, etc.? Thanks.