Ok so yesterday I purchased a used Samsung Galaxy S4 from a seller on craigslist to replace my current S3. The S4 did not have a sim card in it though it was originally with Metro. With the seller by my side we visited a local Metro dealer and they said that the phone ESN was fine/valid. I pulled the (orange) Sim card from my S3 and tried putting it in the S4 but get a Pin code unlock screen for the Sim card. Is it expected to see the unlock screen? or should I be able to activate it with my sim and something is wrong? I just want to know before I go out of my way to buy another one.