If you purchased recently and haven't driven much, I don't see why they wouldn't swap your tires with an ES that has all-season tires. They'll do everything to please you until you've sent that Lexus Customer Satisfaction survey in.
Anyone know which all-season tires Lexus uses for the '02 ES (bridgestone turanza?), and whether there's more than one kind of summer and all-season tire that they use?
Mine came with the Toyo Proxes J33 summer tires, which is fine year-round for driving conditions where I live.