I understand your predicament. I would let him install the brackets and you can always paint them later. Just get that car back. If all the parts were there, 7 weeks is a very long time for an install. I could see 1-2 weeks if it were a busy shop and again, if all the parts were there. A
Re: the paint. As mentioned by several others, calling the builder directly is your best bet. Don't feel like you are "bothering" him/them, you are a legitimate paying customer with a quick, simple question. GL.