Does anyone recognize the lug nuts/studs in this photo. These are different than the ones on the front of my truck. These are the rear wheel dually. Why do they have the square shape at the end of the stud? I am having trouble getting the lug nuts free. This frame has been sitting outside for a couple of decades. Any tips/info/advice?

Lug Nuts


1955 Chevy 6400 2-Ton
LewyBoys' Garage