Everything has been declassified on the chieftain, everything electronic is so outdated now its not even funny and people like me wouldn’t have them in private hands if they were top secret.
Also, even though it’s not the correct Mk it still wouldn’t require a model change. if it had the still brew it could go in the MK10 model or if not, it could just use the MK5 model.
Mine was upgraded to the Mk10, then finally to the Mk11 but i can’t find any information on when it was upgraded to the MK11, but it has the togs on it now.