They are individually voiced. I wish I was a bit more fluent in voice speak to adequately describe them but I can give you some of the differences I'm aware of:
Alder (SS) vs. Ash (AL)
Dimarzio (SS) vs. Seymore Duncan (AL)
The AL also has a plated bridge pickup for more of a tele vibe and I believe Albert was involved in the final voicing of his Sig ax
I believe the SS was voiced for more of a vintage feel over the original Silhouette on which it was based.