BB (RIM) :: BBM Can Be Used On Stolen BB?

My father bought a blackberry bold of a friend about a year ago for $150.00. Now that we look back on it we are suspecting that the phone is stolen, it came with everything in the box (case, charger etc.) but no warrenty card, manual or box, he says that they were lost in a recent move. My father was able to get his gmail account set up on the device, but hasn't tried bbm. I will be taking over his phone later this month and plan on using bbm heavily, if it is stolen will I be able to use bbm? Does rogers (locked device) block the PIN or is it RIMs job? Is there a way to get around it? I am unable to check the PIN as the screen has cracked and is no longer viewable (plan on changing the screen and bezel etc).