Just to play devils advocate, this bass was made probably 3 years or so before Bass Direct sold Grossman basses, and from what I can see they are selling one Grossman basss commissioned by themselves so I'm not sure where the link is between the defect on this bass and Bass Direct unless it's just to try and get in contact with Christian through Bass Direct.
I would also be surprised if after speaking to Grossman that they had anything to say about this as A: it may have been a customer request or B: it might have been sold with the defect mentioned.
I would think your best bet is to speak to the seller and understand why the 'defect' wasn't mentioned or shown in the advert.
Realistically, IF the bass is a quality bass in all other areas, IF it sounds and plays well and has been built well (bar this issue) then there are a number of cheap ways you can mod the bass to be 'correct' from using a dot of black nail varnish (assuming the dots are black) to make the 12th more noticeable (maybe 3 dots?) or speaking to a luthier about professionally dealing with this, perhaps the seller would refund a small amount to allow this to happen.
Just a few thoughts!