Almost certainly a fake.
Just for the record, the RSK Mk5 is made in China.
Just curious how you can tell it is a fake. There is a lot of stuff being made in Chinese factories that does not make it to normal sales channels but still is the real thing. Is there some clue in the picture of the item that is not real obvious to me?
If I told you, I'd have to kill you.

Generally speaking, the industry tries not to educate these thieves by pointing out the less obvious telltales. Then they just make better fakes.