See my post tonight here, which I wrote before realizing that Leon had weighed in on this. There is NO WAY that PSA should call a 100-year-old card authentic when they knew or should have known that the back had been redone and the card retrimmed -- within the past two years, and after it had been slabbed once before by SGC -- in a manner that obviously was intended to deceive.
http://www.net54baseball.com/showthread.php?t=145067