Don't think so Adam................The Anniversary came out a few months before the GS and the GS Spyder a year or so after that. It makes no sense to build a GS Spyder and then stop making them only to start again a year or two later...
I now about it .... Don't think its forgotten if you are a Maserati fan just its an odd buy where most want the proper thing....You can get a great GS Coupe for the money and a GS Spyder aint much more.