Good question - hope someone can give a definitive answer. I take it yours is a UK car?
I've read different things about the Bose system - some people have said its not coded at all, others have said its coded to the ECU (which might cause a problem in your case if its true). I believe i have all the original documents, handbooks, and paperwork for my car and there certainly doesnt seem to be any sort of security code for the Bose stereo.