Hey sorry about that. Thought it was one of those situations where if you have the 28160 wheels you had only one kind and size of stud. Yes they are 11/16". I too have a Gm parts catalog. And found an 11/16 stud part no. that I chased to a dorman 610-158 which is 3-1/4 long. I have in the glove box an extra replacement stud that is just shy of this length by about .004". Since there is no stud sticking out more than the others around it I can see there would need to be an even longer stud.
When I purchased the truck it had a broken stud which I replaced and had purchased this extra one to keep Murphy away. Tom