FYI,
Studs engage more of the threaded hole in the block than a bolt. A bolt, by design can never go all the way to the bottom of the threaded hole. If it does, there would be no clamp load at all. Proper stud installation includes taking a bottoming tap and cutting/finishing threads all the way to the bottom of the threaded hole. The stud is then threaded in as far as it will go.
My Thoughts: A stud may provide some additional protection against this type of damage because it pulls on more material in the block. I have a friend who is a fastener engineer. I'll ask him for his opinion.
I think Neal is right on target with his comments: Steel crankshafts will flex much less and therefore the crankshaft will not load the 2 center caps.
Dave