I just called Doug's to be sure and all they could tell me is they can only guarantee that MP part number they list will fit, and that various Denso starters can vary dimensionally, like other posters have mentioned in this thread.
I'm going to pick up both a mini-starter and the 5.7 starter I ordered yesterday, and whichever one fits best and costs less will be my choice. Of course if only the 5.7 fits then cost goes out the window. But I can bring them both home and try them, then return what I don't use.
It is the top one, you can see threads in some of the on-line photos. Which is good, because you can hang it on the stud and not have to fight with it to get the bolt lined up.