Back when certification was young the services, except for ANACS, did not identify varieties, ANACS would for a small fee. The main reason for this was probably because PCGS and NGC were basically GRADERS. They had no experience with and were not qualified to identify varieties. Then as certification caught on workload increased so much that it just wasn't practical. When you have 20 to 40 seconds to grade the coin (and supposedly authenticate it)you just don't have the time to determine the variety as well. Now ANACS (as an
ANA organization) DID have more experienced people and the reference library and the lower submission rate that allowed it. As the big two started branching out, they started listing the major
RedBook varieties and seriously botched them. PCGS has never really moved much beyond the
RedBook varieties. I supposed they know their Peter Principle level when they see it. NGC began a couple years ago to start listing some varieties on their slabs and then suddenly when Volume II of the fourth edition of Cherrypickers came out they decided to list all or the Cherrypicker varieties. Then about a month later they decided to keep listing the varieties, but they listed them by their own VP numbers which did not match any published standard reference, and they never published a reference for them either. Although they have never announced that they were doing away with the VP variety listings they don't talk about them anymore either, and they do still list Cherrpicker numbers. but there is a problem there as well. They may not do it on the extensively collected series such and the large cents, and Overtons, but on many of the "lesser" series their approach to attribution seems to be "Well it kinda looks like that one. We'll call it that." I'm not sure if we have found a correct CP attributed
Shield nickel yet. NGC started attributing Conder tokens. They are a joke Wrong county, wrong city, wrong edge, wrong denomination, wrong D&H #. ALL ON THE SAME COIN!
Basically for either of the big two NEVER just accept an attribution on their slabs. You MUST always double check their attributions, and you will find them in error much to often. Before the sale ICG did a better job and ANACS did a much better job. Of the major services the best at attribution is SEGS, but they are weak on attribution moderns. For anything before the 20th century though they are better than any of the others.