OP, the seller stated it was going to arrive in an after market case but you still choose to Buy it Now.
So, to answer your question, yes...technically you should be "stuck" with it because it was you that bought it as stated.
Does it really matter? Well, that's going to be up to you however, there are plenty of times people buy things and toss the original box but never get around to using their purchase. So, is it possible the game has never been played? Yes, it is. I have a step son that stores all of his xBox games in his own cd organizer case the minute he gets them, lol.
I'd suggest that you wait until it arrives and make sure it's as stated..then, if all is good...play it and enjoy!
•
