I spoke to Dexstar today and was told that their steel wheels do not have a taper in the holes. The lady I spoke to also said that their wheels do NOT require a special lug nut. Their engineer isn't in today and I am going to call back again.
I snugged up the lug nuts today fairly tightly before heading off. Did not torque them to the 90 - 125 lb-ft they specify. When I got to my destination about 5 miles away, I found the nuts all needed to be tightened a fair bit. Not a good thing I would say. Makes no sense that a tapered lug nut is supposed to work on a wheel hole with no taper.