I say build the bike however you wish. I feel that the value of any bike is not what it is made of or how much it costs, rather how it rides and what you use it for. If this bike is still going after 34 years chances are you get many more years of great value from it after a bit of effort and care. Without a doubt I would replace all the components with wear and tear. Spare parts are so cheap on wiggle and chain reaction that upgrading an older bike with quality components is a viable option. As an example I upgraded my old steel touring bike (at a fair guess 15 yrs old) with brand new 10 speed XT group set, Mavic A319 touring wheels, butterfly/trekking handle bars and just about everything else. The only original components on the bike was the frame, forks and seat post. Everything else was replaced brand new. The total cost of the upgrade came to about $750. I consider this to be extremely cheap when compared to purchasing a brand new touring bike to a similar spec. I wouldn't expect to get much change form $2000 for something in the same category and range as my old steel bike. I imagine my old steel bike in its current condition will outlast just about every high spec carbon bike being purchased today. Since the build I have ridden across Russia on the bike and use it as a day to day commuter. I have put about 3000 km on it since the build about a year ago and the bike never misses a beat. For me it is money well spent.

As for the paint job, I would look for a local powder coating company and ask them to sand blast the frame then powder coat the frame. This would not be the cheapest method however you will get a far better end product. Then reassemble yourself, if you run into trouble take it to your LBS.
Once it is pulled apart it; inspect the frame, particularly around the bottom bracket, carefully for any cracks. If there are any cracks then the frame is probably at the end of its life.

Good luck with the build.

Donnie