I'd Leave it in. If the sound of the J pup is the problem, disconnect it but don't bother with all of the aggravation of filling holes. matching wood grain, refin… In reality, a '73 P isn't the holy grail of basses and sometimes the effort to restore such an instrument isn't as financially rewarding as it would seem. If it was a custom color prototype that somebody hacked up, that'd be different. You can always flip it for an unmolested '73 P.