Yes, there is a difference, but anyway, I still believe after playing a new guitar for 72 hours the result should be comparable. Guitars need to be played. Thats it.
Jame Taylor and Paul Simon have been getting something like this done to their new acoustics for a few years now before taking ownership...they have some sort of a machine in the workshops that shakes the guitar for a period of time that equivelent to it being played for 25 years or something crazy like that...Yamaha are doing it with their high end electric guitars as well i think....
I read somewhere about an artist that would leave his guitar on a stand next to his cabinets so the sound would influence the guitar. after a whole tour of doing that he would start using the new guitar he had had on the stand for the whole tour. I think its a simillar idea but whether its really a huge difference on electrics i doubt. the artist in question was a solid body player. for acoustics i could imagine it making a difference.