I have a great relationship with the dealership that I ordered my car from. That being said, I doubt that they would ever try to be dishonest with me about the status of my car.
I would go in and talk to the sales manager and let him/her know you were unhappy with the attempt at dishonesty the salesman tried to pull over on you. If you're willing to let them display the car, they should be open to your terms. If your trading in a car, you could get them to give you a larger amount for it to lower your payments, get a couple of "add ons", free window tinting, etc. This is where you actually have the upper hand on them. Make sure that they relize that when you're working out the deal to leave your car for XX days.
If you have a good relationship with your dealership, they should respect your wishes and take care of your car. If you don't get the feeling that your new investment will be in good hands, take her home.
