Can I use these Rocker Studs on my heads?

[dencon]

A buddy of mine told me that I cannot use these studs on my heads without getting the stud bosses machined flat. My heads are already taped for screw in studs and I have test fitted these. They screw in. But he said I have to have the heads machined. Is that true?
He said that I have to get the studs that do not have the hex.