I actually work at Target part-time right now and I work at the customer service desk. Yes, you can return without a receipt. However, you will get the lowest price that the item had been priced at within the last 60 days (I believe it's 60). Also, the computer system generally doesn't allow you to return more than $70ish per year without a receipt using your drivers license. It sounds like you haven't done returns though without a receipt, so as long as it is under that amount you should be fine.
If it is an old item or some special item (you never know what the computer will do), then what may happen is that you have to go spend that money in the department the item came from.
The computer system is sometimes really touchy but as long as the item is under ~$70 you should be fine.