A "Black Betsy" Joe Jackson game bat sold in a Sotheby's auction in 2008. It doesn't have much resemblance to the Erwin. The Sotheby's auction featured a Joe Jackson Black Betsy game bat from the collection of Dr. Richard Angrist.
link from old Beckett article:
http://www.beckett.com/estore/news/?A=9320
I also seem to remember in the late 90s when Upper Deck started that 500 home run club bat card craze that they also had redemption cards in their products for memorabilia and one of the cards was for a "Black Betsy." I could be wrong, but I distinctly remember seeing a photo of the man who won it in an old issue of Beckett.