I had Line-X done when I got the new truck a year and a half ago here in Grants Pass, Oregon and it was $400 without the top rails done. So, your price sounds about right. I did not want or need the top rails done since I was going to put a camper shell on it anyway. If you plan to load a lot of stuff into the truck bed from the sides, then it mahes sense to have them done. My guy also did gun stocks with Line-X for $75.
Dave