Bmw stereo code

hi i have an bmw 318i se 2003, which came with a tape player, mates given me his cd player to try out, but the thing is he does not know if it will ask for a code or not, i want to test it by placing it into mine, but the thing is i dont even know what my code or if it does not even have a code?

any solution anyways i can get the codes or anything? even if i can just get my code atleast then i can test his unit and go from there, or if i disconnect my one and reattach it will it ask for code or not?

thanks
hnj

they don't have codes