There have been numerous forum folks that received those and they were in fact preapproved. I wouldn't accept it, unless you'll really use it and you need a store card in your credit mix. They will likely approve you for their typical $200 that has a max growth potential of $500cl these days (I did read that the earlier years of the REDcards were more generous, but not anymore) with the slim possibility that you will do something magical that may eventually bring them to offer you the Target Visa. Not sure what kind of fairy dust you need to get that card, but many of us are waiting after 2, 3, and I think I saw someone who said like 6-7 years. 
