If they are PCGS graded they should have a designation of some sort. You can do a "cert verification" and it should show you some information, grade, maybe variety, and if the person decided to image the coin, it will be there asw ell. It should show coin specifics including the overall price of the coin.
Additionally, you can hit the PCGS.com site and under COIN PRICES you can navigate to the type of coin in question. Find the year of the coin, and if the far left column has a "+" plus sign that is expandable and may show mint errors under it.
NGCcoin.com is another area to look. NGC has a Variety Plus listing which is cool. Go to the NGC Research Tab, then variety plus is on the pull down menu. It offers a cross reference of most of the major companies/people that deal with errors and may show some subtle changes.
It could very well be the coins are of a particular variety, but may not be the best example due to a variety of reasons.
CONECA is another awesome resource online, and the
Cherry Pickers Guide from Whitman may also list the coin. if it is not in the front of the book, there typically is (was?) a quick reference chart in the back of the book which may list the varieties.