Hey, I bet the cards are authentic!
I always looked at GAI as a couple steps below SGC/PSA because they assigned a lot of numerical grades to trimmed cards. I always felt they did just as good a job of not slabbing reprints but boy did they slab a lot of trimmed cards. I'd never buy a GAI card that looked trimmed because it probably was, however, I'd always pay a discount on a GAI slabbed card if it looked like it wasn't altered.
Oh yeah, better add, I would hope that the auction house pulls the packs if it is brought to their attention. They can't pull something from the auction if they don't know it's bad. Also, I doubt they would have put it up for bid if they knew there was an issue with it.