From a legal standpoint, yes. From a customer service standpoint, maybe GM would take a different view. It's not GM's fault the dealer didn't call the customer, but the dealer does represent GM. They may think it is worth offering the small MPG rebate to keep a customer happy. It's worth giving it a try, but not worth getting worked up about.
Reeking out those last 2 mpg is tough, tuned. I wanna Rev....