But regardless of the financial value of the guitar, and whether or not there's any intention to sell, there can still be a "sentimental" value in the fact that this particular bunch of parts have been joined together as a guitar for the last 44 years..... and it just seems wrong to mess with them.
On the other hand, if the guitar's already been significantly modified, or something's actually defective, I think you should do what you like. If I had an all-original 1964 guitar and one of the pots broke, I wouldn't go looking for a 1964 pot to replace it - I'd only feel sentimentally attached to the original pot!
I realise that's not a hard-headed rationalist argument, but it makes sense to me. :|