Posted By:
davidcyclebackI would buy a $10 black light and see how the card fluoresces. If it fluoresces brightly, it's modern.
I would then get a microscope and see if it's photoengraving printing, which would be consitent with the period. If it is or isn't would prove definitely, but would offer insight.
If Bill Mastro and Rob Lifson all say it's not original, that's as good of evidence as anything. I don't know of an experienced collector who would buy a card knowing Mastro and Lifson are of the opinion is fake. That would comparable to buying a Babe Ruth autographed ball knowing that it had considered fake by both PSA/DNA and JSA.