Correct. Texas A&M alumni here. Our 12th Man has a 90 year tradition. It was a bit of a shock moving to Seattle and seeing that they had a 12th Man too. It wasn't widely known at the school until the Seahawks went to the Super Bowl in 2005. Shortly afterwards the two teams reached an agreement that worked well for both of them.

But there, it has a different meaning. The twelfth man can play. http://en.wikipedia.org/wiki/Glossary_of_cricket_terms#T:

Traditionally, the first substitute player who fields when a member of the fielding side is injured. In Test matches, twelve players are named to a team prior to the match, with the final reduction to eleven occurring immediately prior to play commencing on the first day.