Well...I am not sure why the "60%, (80%, 75%, or 90%) of the tone comes from the mouthpiece" thang is still bandied about by some as da' truth....because the fact is, as I have said ad infinitum....a sax has tonal/sonic qualities built into its design. Body tube, neck, bow specs such as taber, dimension, bow radius, neck length, tonehole location, tonehole diameter, and possibly tonehole stack heights are all specs which vary from maker to maker and give certain makes their signature sound. Slap whatever piece of plastic or rubber or metal or wood you wanna at the end of the piece of hardware, the hardware still will have the designed-in sonic qualities of the hardware.
With that said, certainly a mouthpiece setup can lean a horn one way or another, sonically.
OK, end of soapbox.
+1 to Turf's answer above. The 'aging' of metal in a wind instrument imparting a sonic flavor to the tone ? I would say no. In the case of cymbals, most certainly it can be said that older bronze 'calms down' with time, and the sound of a cymbal will 'settle'. Something most percussionists believe, in some version of the semantics. However, this may not be due to the fact that the metal is 25 or 75 years old so much as due to the fact that patina usually develops. The alloy composition definitely has an effect on tone, because again, you don't blow thru a cymbal...you strike a cymbal with a stick.
Not so much a sax (although there are some boutique brands out there which would tempt me). So the cymbal is spending its life being struck and then vibrating. Not so much a sax (although again, ditto the comment above - there are some which I wouldn't mind crashing every day).
When you speak of strings, you get into Resonance, and the fact that (of course) the plucking or bowing or strumming actually makes the wood body resonate. Does Resonance play a huge part of a saxophone's sound, however ? Most would argue not (although today many marketing depts use this herring). Also, wood is wood. Metal is metal. Different stuff.
An interesting experiment, for someone with oodles of ca$h lying around...would be to break down the specs of an old model, say a Martin (this is NOT hard to do as machinists and industrial designers have such equipment that can scan and plot dimensions and specs of an object)....then literally build one from scratch (which becomes much more challenging).
I would not even be so concerned if the alloy composition of the contemporary brass did not match that of the original. But body gauge, weight of keys, construction of toneholes, etc...yes, would need to match.
MY educated guess would be, if an exact duplicate was constructed....it'd sound (and respond) just like the original. Age of brass, alloy composition, finish (lacq, plate, bare) would be negligible variables.
My thoughts.