I have a credit rating on the borderline of poor, with a credit score of around 670, do you think I would be approved for the Target card?

Store cards tend to have a larger window as to what kind of credit score is acceptable to them. Some stores, have several versions of their card. The store card that is co-branded by Visa or MasterCard would require better credit than the basic store card. However, most store cards usually do not approve people with bad credit. In your case it could be hit or miss. In other words, I would not apply for it because you cannot afford to lower your credit score any farther. If you submit an application, it could cause a hard pull on your credit which could lower your score even more. It is not worth it for a card you might not get. Go for a card that is specifically aimed at your range of credit that can help you improve your score.