Is this all installed in an axle or are you wanting to know if you have a carrier loose (i.e. not attached to anything to give you an indication of ratio) how to tell what series it is?
I personally wouldn't use a Gov-lock for anything but maby a small boat anchor or a door stop (I don't even think it would do a good job at those tasks). I have seen too many that looked like someone pulled the pin on a gernade and tossed it into the diff.
This is one example of how they got the name Gov-bomb