Well, normally the iOS 5 setup will ask you for your Apple ID during setup as seen here:
Image
But if you used iTunes to restore it it most likely signed in with your Apple ID that iTunes is signed into and skipped it in the setup on the iPod itself. I know my 2nd gen does that on iOS 4. If you reset it on the iPod itself it will ask and will be blank.
I wouldn't worry too much about it though, you still have to provide a password to purchase things, and the new owner will most likely use their own. But for future reference, you will want to go into the settings and check things like iCloud, Mail, iTunes and Appstore IDs, etc.
Or restore and then erase content and settings afterwards to make sure it's clean.
Was this a 3rd generation touch? Just curious. It's the only one that stopped at iOS 5 and would be eligible to restore in iTunes with that version. Miss mine, it died a premature death in 2010.