Owning vintage basses is in my experience a very rewarding thing to do. My recommendation would be to save a little more and buy an all-original example. Refrets or minor hardware changes are not the end of the world, but if the body or neck are refinished, however many original parts you source to stick on it, it is still fundamentally undesirable to most vintage buyers.
I have three pre cbs jazz basses, all original. I am just about to buy a refin pre cbs strat - mainly because I will never be able to justify to the chancellor £10k+ for a fully original one, when it is not my main instrument. To me, the only reasons to buy a refin Fender bass are that it's either so cheap it would be rude not to, or that you'll never be in a position to by one with the original finish