I would expect it to be bolted, however, if you only want answers from KMG owners (which isn't unreasonable), I would suggest going and signing up with BladeForums and asking on there. KMG refuse to sell to anyone in the UK, or they did do some years back and I would expect that their position hasn't changed, so you probably won't find many owners of genuine KMG grinders in the membership here.
The other thing about Bladeforums is that there are quite a few other grinder build WIPs that are worth a look. There might be some on EdgeMatters too, but BF has been around that much longer and has that much bigger membership, so more choice of reference material.
As for making a KMG clone, there are some interesting comparisons of the KMG vs the TW-90. Would making a TW-90 clone be that much more difficult for you? The TW-90 is generally considered a superior grinder, in part for the design.
https://www.bladeforums.com/threads/kmg-moag-or-tw90.1623719/
https://www.bladeforums.com/threads/tw-90-or-kmg.1171949/
Whatever you do, how would you feel about shooting some photos as you go and posting a build-thread when you are finished? That would be good
Best of luck!
Chris