yup, amcas sends out some preliminary info, like your address and email, and provided the school doesn't screen, you might get a 2ndary before verification.
schools definitely send out secondaries before your fist application is verified. Be careful though, and double-check with AMCAS periodically. I was went an email verifacation after submitting my application from them and received all of my secondaries (and even starting interiviewing) before my application was actually verified. I would call and double-check everything with them!