I have the same doubled up wires, and I think that it's factory. But it does look like you only have 2 connections, and I know there should be 3. It looks from your first photo that there's a wire folded over and wrapped into the harness, might that be another connector?
Here's how my working rheostat was wired before I unhooked it and put in a three-way jumper instead.
Jon
1981 DMC-12 #02100. July 1981. 5-speed, black, grooved w/flap. restoration log, March 2011 to present
full and detailed photo restoration log