Guitars with lacquer rather than french polish would probably be quite difficult to repair. If you're not worried about aesthetics I really wouldn't worry about it. I personally like the vintage look, which is the charm that comes with a 40+ year guitar. There is a very low chance those dings and such will pose any problem in the future, unless you like to pour buckets of water on top of your guitar
In regards to the crack on the back, I bet it happened long time ago and has been stable since. I doubt it poses any structural compromise based on its location, but you'll want to get the opinion of a luthier. I know of people with vintage ramirez guitars that have cracks, and they actually don't repair them for fear that it might change the sound.
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