I seriously hope not. The Reiko/Kahn thing needs to die, get cremated, be buried at the bottom of the ocean, and forgotten.
Figurativly speaking of course.

I thought that mistake was completely explained as being false.
Ka-Tra

It was. Ed Boon and John Vogel both confirmed that Reiko is not Shao Kahn. Hopefully, he's not even Kahn's "decoy."

ya then i wonder where reiko is

If you remember in Konquest, one of Kahn's missions was to tell Reiko to stop secretly putting on Kahn's helmet. This, of course, proves that Reiko is not Shao Kahn, just for some reason likes to wear the helmet.