It's not an after production "cartouche" variant - it's a 60th birthday watch he ordered and gifted. Many other examples and even a 70th birthday variant. It's an impossibility to me that these are not delivered like this from the factory
Also to my knowledge Omega didn't make these dials anyway, the case, the dial, the hands are all from other manufacturers.
The Korean day disks also are(were) exclusive to these watches. They are all around special made. So even after all this information if anyone is going to claim they are aftermarket modifications, it will be more obvious they are trolling.
Also let me note that my interest in North Korean watches are purely from an Omega enthusiast perspective.
He also had a 70th birthday variant made that had a C-Case delivered in 1982 that has a serial that dates to 1979
And if the validity of such obvious watches are in question even among enthusiasts, it proves my point that these later extracts actually hurt irregular watches, while the head of the museum was faking his own irregular watches