If you think that the verbal CogAT score isn't representative of her abilities and that what is *actually offered* in the school's gifted program will be a good fit for her, then, yes, I would appeal.
It is possible that she didn't understand the directions for one of the subtests. For example, as a kid for years I didn't understand what I was supposed to do for the analogies sections of standardized tests, and from what I remember, they were on all of the tests I ever took growing up. It wasn't until the SAT when my aunt who was helping me prepare finally explained it to me.
If it was a paper and pencil test (I don't know how the CogAT is administered these days), she might have also gotten off on the bubbles. I think the computer doing the scoring is supposed to be able to pick up on that and flag the score, but I could be wrong, and I don't know if the school would tell you if it happened.
