The answer to the first question is, ultimately, you never really know if what you have is authentic. Too many plausible things over the years have been exposed to be forgeries, and some of these are frighteningly competent - some so competent that their perpetrators have become collectible in their own right. And, what's worse, many forgeries likely persist in the marketplace, either undetected, or forgotten to be forgeries and recycled or re-fed through the system with spanking new COA that contradicts what had been established earlier. But the question needs to be asked anyway if for no other reason than a dealer can provide at least some assurance of authenticity, hopefully enough to persuade a collector to pull the trigger. It isn't the purpose of this article to explain how to go about this, but obviously comparing "known" exemplars to the signature in question and investigating provenance, if ny exists, should be high on any dealer's to-do list, that is, the dealer should be satisfied first before offering anything asserted to be genuine.

The answer to the second question isn't a slam dunk either. There are collectors who insist on getting a COA with anything and everything they buy. The trouble with this is that many dealers who issue them aren't themselves especially qualified to evaluate handwriting, and mistakes are made. Sometimes even so-called experts make mistakes - or, more cynically, commit fraud. Pawn Stars own Steve Grad, the dude with the tablet and magnifier who has authenticated who knows how many items on the show, has at best a questionable past, doubly troubling because he is PSA's principle authenticator, and everybody trusts PSA, right? Right? If you have a few minutes to blow, take a look at this.

here

The takeaway lesson is not to put blind faith in anybody - and this is the basic lesson in Stephen Koschal's book. What I like about Steve's books are their specific focus, and in this one he zeroes in on Angelina Joli, offering numerous examples of signed eBay items presented as authentic when they are obviously not, including forgeries, secretarial's, autopen signatures and more, many of them with "comforting" COA's from so-called legitimate authenticating services. You may ask, is eBay a reliable venue for purchasing autographed items? The short answer is no, of course not, which isn't to say that genuine things can't be had if one follows a common-sense protocol. More about this some other time.
Meanwhile, know that there is so, so much questionable material circulating in the general marketplace that it could - and often does - paralyze buyers from purchasing anything. What are we to do? Steve's answer to this is to maintain a list, updated monthly, of "Preferred Autograph Dealers." Or PADAH. His criteria for inclusion: "Each and every dealer on this list has been hand selected, is totally professional, has many years of experience and will treat you the way you want to be treated." As of February, 2019, there are 58 dealers on the list, which, by the way, appears toward the end of his book and may also be accessed here.