In pure finance terms the car you order should be the same price, or even cheaper than a car off the lot. However, the sales team is looking for immediate gratification, so they would like to sell a car off the lot instead of waiting for your delivery to get the commission. Special orders for customers are also tagged in the computer system so they can’t be redirected to another dealer, and they should have production priority so they get delivered sooner than cars purchased for stock. Dealers also get incentives for volume and selling less desirable vehicles, and that incentive might end on a certain day, so they might want to sell a vehicle right now to get the incentive.
When they order a car for you, a few days later they will get a message asking them to confirm the build. You want to see this message because it confirms exactly what will be built. For example, if there is a running change in option configurations (what is included in a package, etc.) or colors, it will be listed in that message.
Bruce