This item is currently up for auction on ebay as of 12/4/11 item # 110786763257. The seller is claiming this item is signed by heavyweight champion Jim Jeffries, James J. Corbett and contender Tom Sharkey. This item originated from an auction house with the blessing of a third party authenticator. Compare the writings under the heading "Monday,  June 13, 1904". Is it hard to tell that the signatures, maybe aside from Jeffries, are all in the same hand?

auction house listing backed by third party authentication

ebay listing #110786763257
 

A vague third party letter loosely written claiming this item is signed by "James Jeffers and others" Who is "James Jeffers" and who are the "others"?