iOS 7 isn't available on 4th gen iPod Touch
Sadly, no. The latest version of iOS for the 4th Generation iPod Touch is iOS 6.1.5.
No, only iPod Touch 5 can use iOs 7
No it did not. It had IOS 6. But you can get IOS 7 on it. Also when IOS 7 came out they put it on the iPod 5 in stores.
The only iPod that can run iOS 7 is the 5th generation iPod Touch.
ios 7 is coming for ipod 4g on september 27th! (today!! :) )
No
Possibly
Ios 7 is the latest ios. Ios 7 is available on the fifth generation iPods, recent iPads and iPhones 4 and 5.
The 2nd Generation iPod Does not have the processing power to run iOS 7. Neither does the 3rd or 4th generation. Only the 5th generation iPod Touch can be legally updated to iOS 7.
You should be able to. Speculation at this point is that users with ios6 will be able to upgrade to ios7 with no problems.
There is no way to undo iOS 7 after restoring your iPod because iOS 7 is not released yet. However, to downgrade the iOS of your iPod simply download the firmware of the iOS you want from the Internet. While in iTunes, hold shift as you click "Restore my iPod to factory settings" and choose the file you just downloaded and your iPod should be on a lower iOS.