No, they are swedged to the drum. In other words, the drum is placed over the studs and then a machine presses the drum area around each stud, distorting it so the drum pretty much becomes part of the hub.
I have used a 5/8"metal cutting hole saw with good success to cut the swedge away from the stud. Even still, it is best to center punch the broken stud so it will collapse when you drive it out. This way, you will not hurt the hub. If you don't drill a hole in the stud so it will collapse, you will ruin the hub and a new stud will not press in.
