I am not convinced. And I pride myself in detecting that that "Thunderbird" in the one vid in the TBird thread was a Victory, because it sounded bolt-on to me, so there! What more scientific proof do you need?
In my ears, the note on a bolt-on develops quicker (attack), but doesn't last as long (sustain). A bolt-on is more upfront and precussive. I always put that down - quite simply - to the different length of the necks. I'll admit that I'm not so sure whether I could always identify a set neck from a bolt-on or a set neck from a neck-thru. That said, I find all those Grecos and Orvilles (you guys always rave about) lacking in the sustain department around the 10th/12th fret, even the set neck Gibson NonRevs aren't quite there for me. They have sustain, but it is not the melody-playing-enticing sustain of a TB Rev or a Ric 4001/4003 up there (though a Ric also has plenty of attack, I put that down to the maple construction and the single coil pups).
None of this is ever a determining factor for the audience, only for us acoustic trainspotters. Of course I can survive a gig with a bolt-on as well. My favourite bolt-on is probably the Gibson G-3 with its hilarious snappiness though it reinforces my already busy and attention-clamoring (people say) playing style so I tend to play "slower" basses.