DOT approved = approved testing for use on highway
Non-DOT approved = no approved testing for use on highway, so limited to military, farm, or industrial applications: ie, offroad only.
But to echo Goatman, just run them anyway. I have only ever seen one ticket given out, and that was by a cop who was a 4x4 enthusiast himself and knew the difference, and who was waiting at the highway after a long run just to bust any 4x4's that did not meet highway equipment regs.
Also, although you see DOT approved beadlocks for sale here and there, the cheapo route is to have new centers welded into a set of hummer wheels with the factory beadlocks. That way you can have them with custom offset for your vehicle and bolt pattern.
Buck :canada: