I don't think that they do. Unfortunately, wear on Corvette seats, both C4 and C5 is extremely common. I'm not sure if it's due to the design where the side bolsters curve in sharply, or if it's due to the quality of leather used.
The only thing I can suggest in order to prevent any further wear (and most people don't like to do this and think I'm crazy), but keep a large cloth or towel on the seat before getting in. I use one of the old mechanics cloths that mechanics used to place on the car while working on the engine. They are soft cotton, extremely comfortable and do an excellent job at protecting the seats. After putting 23K miles on my own C4 Corvette, my side bolsters look as good as the day I bought the car. Obviously, this isn't prudent if you're going to be racing the car because you're bound to slide around in the wider C5 seats.