No, there are concerns with any bike. The frame could be bent. The bearings could be shot. The seat tube could be frozen in place. You will quite possibly need to get your hands on a couple of tools that are a bit outdated - A freewheel tool, a cone wrench, a bottom bracket tool, etc. Nothing expensive or crazy there. I agree not to worry about frame brand because at this point you are making a frankenbike. I would stick with a steel frame - much more agreeable to bending and cold setting if you need to spread the frame to fit a different rear wheel. Bike wheels have gotten bigger over those 40 years for speed, also wider to fit more gears and also disk brakes.