I bought used, and I got two.
For $12,000, they can either give me two keys, or ride that car like a dime-store pony, because I wasn't about to leave the lot without a pair.
Seriously, the keys cost $70-$90 or something? If they don't have one, they can make one, and it doesn't cost them half that much to do it. They're not gonna lose a car over a $20-$30 key.
I make the older style GM VATS security keys at work. The retail price for a key is $27+tx. The average cost for those keys are $6-$7 per key. Granted, there's supposed to be a profit margin, and granted, there's supposed to be padding for error when you cut a key wrong and have to throw $7 in the trash.
Demand a key, get a key.