I was told it was only a little over a year old. Of course I can’t verify that. I just have to take his words.
if this is important to you (and I am not saying that it is) you could probably call or email the people at Mac and if you gave them the serial number they could probably give you date of manufacture and possibly other odds and ends.
He said the unit hasn’t been played for a while, and it will require some break in time again.
If it had been recently retubed, perhaps? I've also read posts abour capacitors needing some running time for them to "reform." I cannot personally attest to that, it is just what I have read about on this site.