Yea that is what I keep finding in my search. I found some like this. They say GM but I bet they will work. They are 3/16 stud x 3/8 od I bet they will work
Its a thread cutting nut. A pal nut is a stamped nut also but doesn't cut threads.
Above might work on a earlier panel. The large late model panels have a large stud that is hollow like a piece of tubing. I had stated 3/8 but it might be 5/16. Owner should measure before buying. I think I have the OEM nuts somewhere in my basement. I'm not going to the post office though.