Howdy

The "MK" nomenclature is determined by the finish. So the answer would be that no MKIVs were made with any finish but a polished blue. A MKI would be dull blue. and a MKV would be dull SS and a MKVI would be polished SS. There were many other varitions such as the professional, the MC series ect... But the main constant has always been that a Combatmaster is a Combatmaster and the model number designated finish and or options on the given Combatmaster. Check this sight for more precise info and also check the Yahoo Detonics "group"
Hope this helps!
L8r
Conley Janssen
USMC 87-93