Nah. The decision re: secession was in dicta. Chase's ruling was built on air - nothing in the Constitution prevented secession.
The issue before the court was the sale of the bonds. Incidental to the decision was if the SC had jurisdiction. The court ruled - invented a specious power is more like it - that the state had never left the union. If that was true, then the state legislature could do anything it wanted with the bonds. Chase ruled the state never left, and that the state legislature couldn't change it's own laws. Even Justice Grier, who authored The Prize Cases, noted in dissent that the ruling was a joke.
I've given up expecting you or GOP to accept the same definition of obiter dictum that the rest of the world does. Suffice it to say that the legality of the Texas secession was indeed a central part of the defense's case.