For what's it worth, my local shop said they had multiple adams shafts that were out of balance when new. They only use Toms driveshafts now and haven't had an issue. Second hand information, but I would either send back to adams or have a local shop check balance.
LOL!! I've seen Tom Woods shafts out of balance right out of the box but that'd be the least of my concerns - I'd be more worried about the piece of crap "gold seal" Chinese u-joints that he uses unless you know enough to pay to have them upgraded them to something better. But, I would agree, it's not totally uncommon to get a new shaft that's out of balance and if the OP's is out, I would send it back and have it rebalanced. Sucks but really, what are you gonna do. In a lot of ways, this is why I like using local shops.