i think both name and number are unique. each number has a different audio watermark. so if this audio ever got leaked, they could have checked the watermark, and if the result was for example 25, then they could easily link it to the blacked out name. because there’s only one cd with the watermark \"25\".
so if you really want to \"protect\" the original receiver of this promo, you should also black out the number, or one might assume he sold it on. (he or she could of course always say that they still own it, but sent scans to spfreaks.com.)