I am curious about that myself! And I have a 23 year old Sadowsky which I can say sounds amazing! I am not the original owner of the bass (actually it was made for Steve W. Rabe, founder of SWR), so no idea what it sounded like when it was new. But compared to a Metro I had, the older Sadowsky has a better tone.
But I do know this, I also have a 1972 Fender jazz. I have yet to play a new Fender jazz that sounds anywhere near as good as my 39 year old jazz.