Before wrongful death case was filed, probate court enters an order finding administrator was decedent's common law spouse. Defendant in later filed wrongful death case is now trying to prove administrator was not common law spouse. Seems to me this issue is already decided.
Answer: Your problem is that you can’t bind the trucking company by a finding in the probate to which it was not a party. It has a due process right to litigate that issue. See: State Mut. Life Assurance Co. v. Hampton, 1985 OK 19, 696 P.2d 1027, 1033 (acquittal of wife in a criminal case of killing her husband could not preclude his heirs proving she killed him because of their due process right not to be bound by the finding in a case to which they were not parties.)