Start with getting a deluxe Marti report, (https://www.martiauto.com/martireports.cfm) this will tell you how the car was when it left the factory. Then look it over underneath and inside for any rust. Make sure you know where it has that. Also look it over closely for damage repair. This is important for value. Being it has had a color change that may hide things. But Black is hard to use to hide previous damage. I like the color combination it is now. Having a sunroof is a rear option and people like that. If you have history that helps too. There were 211 color code “D”(Pastel Gray) with interior code “6D”(Red XR-7 Leather) 1969 XR-7 hard tops built. Being a “M” code 351 4v with the Sun roof, A/C and whatever other options this has should make it 1 of 1. As for value? I have no idea, $10,to 20K may be.