Needless to say, it is one of the black listed keys and definitely it will not be allowed by SP1a, even if you owned that key legally. Microsoft has released new keys for those corporations who had this devils0wn key and basically this key is out of the world for Windows XP SP1 installations.
Besides that fact, Microsoft does not recommend installing SP1a for those people who has got SP1 already. So, others please be aware of that fact.