If you have a backup of your iPod touch stored in iTunes, then all of your application settings, including high scores, will be restored as part of that backup. The app itself isn't part of the backup, but as long as the app is stored in iTunes, it will be reinstalled on your device (with all of the settings intact from the backup) after the restore process completes.
The short answer is that if you're using automatic sync with your iPod touch and have everything stored in your iTunes library, plus a current backup of your iPod touch stored in iTunes (again check the "Devices" tab in your iTunes Preferences), then following a restore your iPod touch should be exactly the way it was before you restored it, minus the passcode.
The iPhone doesn't automatically unlike either. All iOS devices are the same in this regard... Plugging it into your computer will reset the invalid password counter, so you don't have to wait 5, or 15, or 60 minutes to try another password, but it won't reset the password or unlock the device.