If you think the car might have sold originally in NC, try doing a DMV title history search. You have to say it's for research purposes and you do not intend to contact previous owners. Have to go to downtown Raleigh DMV office and request it in person, it usually takes them about 15-30 minutes. That could at least narrow down the DSO, although not 100% definitive.
I believe I have seen some work done by the place in Denver, it wasn't concours level, not even close.
I'd suggest taking a bit more time to collect your thoughts on what exactly you want. It can be very costly to correct poor workmanship later. You may want to post some pics of what you have to get more input on the best approach. Shops will want to replace full panels as it's quicker for them and less headache. It's almost always better to weld in patch panels and keep as much original sheet metal as possible. A lot of body shops won't want to do this though... or do not have the skill level.
One other thing, check up in the roof area for a build sheet. My first fastback, a Metuchen car, had one stuffed up in the metal above the headliner. They are almost always taped to the main wiring harness. Someone probably removed it if it isn't there.