I don’t think there is a McDonald’s in North Korea but otherwise - yes - a Big Mac is the same all over the world.
You could be paying thousands of dollars to get your Big Mac in PyongYang, so technically it's available there, and PyongYand residents can there be declared as crazy rich on the PPP scale.
Same way if the measure was Toppogi it would be dirt cheap in PyongYang and Seoul but crazy expensive in Guatemala with one single shop offering it as a delicacy.