This is not a wrongful termination under the legal definition. A wrongful termination does not mean that you were fired for something you did not do or for something that you had permission to do; it means that you were fired for a reason specifically prohibited by law.

By all means talk to an attorney under the theory BOR has proposed, but don't be surprised if it doesn't fly. They should have checked to see if the other employee would go into overtime by taking your hours before they approved it, but it's still a new fact that wasn't taken into consideration. Or so we assume.