My officer indirectly asked me during the interview. When he wanted me to sign something at the end and make sure all the data is correct, my name, birthday, A-number, etc... and I told him, I don't know my A-number (he had my Greencard laying on his side of the desk). But he just said that I don't actually have to check that and that he knows the number is correct since it's on all my paperwork 😆 I guess, it's just a formality. I wouldn't worry about it.