They'll be specified in mm, not inches (or fractions of an inch). As well, rockauto likely has them, just not specifically listed as being for your vehicle (I got a set of lugs and studs from them, and I found the dimensions of the studs elsewhere, then did a part search for them on rockauto).
2004 GMC Sierra 3500 C&C, added 4WD, 6.0L gas, Extended Cab, SLE, Transgo 4L80e-HD2 kit installed
Whee! Dually Club Member #1109