I was going to a university in detroit and living in windsor, Ontario. Yep they did ask me about the residency requirements. Soon after the test I was taken to a citizenship officer. She just confirmed if all the information I put on the applicaton was right. I didnt have my old passport with me so she wanted to look at it. I had to schedule an appointment with her. I didn't have any major problems. She didnt ask me for any prove. I guess she was convinced that I was living in Canada. Since you have Green Card, they are good chances that they will call you for an interview. If you lived in Canada for 3 years, you shouldnt have any problems.