Just had this happen on the balancer bolt. In my last order they sent most of the 12 point the sent these darn 6 points with a little air plane on the bag and the cost was a lot less.
Yes the ones with the o in the head are longer. And arp makes 2 main stud kits for the Dmax but most just use and stock the longer ones it does not hurt anything with studs.
Post 42 last 2 pics might help some
http://www.duramaxdiesels.com/forum/showthread.php?t=5608&page=2&highlight=She%27s
Post 31
http://www.duramaxdiesels.com/forum/showthread.php?t=6679&highlight=She%27s