Special serial numbers were assigned by Bill Ruger to his friends, gun writers and other important folks in the gun industry. A few assigned serial numbers have been given up over the years by their owner when selling their collection. I understand in some cases the person who bought the collection was able to continue to get that specific number. I have never heard of anyone just ""buying"" a certain serial number.
No, it does not seem that RCA Members get any advance notice of new models fro Ruger.