MMhh That's weird they don't care about the date they just make sure that you have the proper IDs in our case we went in without her passport the security guard just told us that we need either her passport or her work permit as identification and to come back with either one of them .We drove back home and got her passport and went back the same day,they let her in.The people taking the prints just took the appointment paper and did the finger prints and that was it.What part of town are you in ?
I'm from MA, but the appointment is at RI...i'm the first I think from the 2009 filers who was not allowed to do walk-in. Anyways, it is just a week away, I'll just come back then.