As has been stated elsewhere, its common in the car industry for cars to be transported uncovered. Cars routinely arrive at dealerships with scratches, chips or whatever, and have to go through an extensive prep process before they are sold.
The main difference with Tesla is that the cars are made to order, and the delivery process (and lack of physical infrastructure/space) doesn't always allow for proper prep work. Tesla has done a lot of work on this front by reducing the number of contractors involved and centralizing distribution operations, but they obviously have a ton of work left to do in order to match the seemingly seamless experience of customers at most dealerships who might not ever realize that their perfect new car had had chips and scratches that were worked out before they ever laid eyes on it.