NOTE: The opinions expressed by these evaluators are theirs alone. eBay does not examine items listed on its site and does not have the expertise to evaluate items. eBay cannot guarantee the findings of these evaluators -- authentication and grading are difficult, often subjective matters where the experts themselves occasionally disagree. Each of the companies listed on this page that provides authentication and/or grading services is an independent company, and eBay is not responsible in any way for any action, inaction, opinion or service in connection with these companies. You should review the credentials of each company and use your own judgment before using a company's services.

Then read the FAQ's

http://pages.ebay.com/help/community/auth-faq.html

Here, I see some help for the seller by refunding listing fees, but no help for the buyer after the sell.

Within the last paragraph of worthy note is,

The authenticators have also pledged not to buy or sell on Bay's core site, thus keeping them out of competition with the very buyers and sellers they are serving.