[83GMCK2500]

The wheels pictured are 2008-10 only. 2001-2007 Classic DRW trucks have a 16"x6.5" wheel with a 4.60" hub bore and an 8-on-6.5" bolt circle, the truck uses 14MM studs with a clamp ring that uses unique 90 degree taper conical nuts. Every other conical nut GM has used on trucks is 60 degree taper (that I know of, 73-present). The pictured '08-'10 wheels are 17"x7" (might be 6.5", only held one once) also with a 4.60" hub bore and 8-on-6.5" bolt circle.

The front end you are using will have a 4.56" hub bore and yes, use 9/16" studs. It will also have the same clamp ring with 90 degree taper conical lug nuts.

That all being said, the newer wheels will bolt onto the older front hubs, I wouldn't worry about 40-thousandths difference in hub bore unless someone else has something important to share in that regard, I doubt it will throw the hub-centricity off too far. You'll just want to use the correct clamp rings and tapered lug nuts.

Your question about the rear axle...what wheels are you running in the rear, need to know to be able to address your wheel stud question.