I've got news on that subject...having recently left the car biz. Most dealerships that are lucky enough to have something like this that will sell for a hunk over sticker will only give a token amount to the salesperson involved.
Case in point. The last place I left had 3 Challengers coming, with two already "sold" for $10K over. They paid the salesperson 10%. same at a Ford store near me that sold a couple of GTs. In that case it was more money, cause they sold for more than $25K over. Still, you would think the dealerships would treat their salespeople better.
But they don't. Most look at the sales staff as a "consumable" to be eaten and spit out. They don't care if you're their top salesman or not....which is why I got out.Top in sales. Promises made and then not kept. They flat didn't care if I stayed.