OK, well I'm not an intellectual property lawyer.
But, for instance, say the Seahawks sell a Jersey in their proshop that has the number 12 on it.
Are the Seahawks the only team in the NFL that have Jerseys with 12 on it? Of course not.
So unless A&M is gonna insist that the entire NFL and all collegiate football retire the number 12, then they CAN'T say that they have absolute, exclusive rights to it.
So I don't see them prevailing in court.
A&M doesn't have a trademark on the number 12. They have it on "12th Man."
They're not pressing this in court, but if the Seahawks continue to market stuff based on their fans being the "12th Man" then they're extremely likely to lose in court if it goes that far.