I have a 1998 DeVille D'Elegance with the factory CD/Casette Head unit with RDS and the DSP controls, I have 11 speakers I can find. Is this a BOSE unit? It doesn't say bose in the head unit itself or anywhere I can find.... is there an RPO code for BOSE? I looked in the owners manual the other day and as I remember this is the top of the line offered except for the trunk mounted changer option that I don't have (yet).