At least for MARSOC, at least according to Strategypage.
Also an interesting article on the state of the M9. And the desire for a more "modern" (despite the Glock 19 being a 30 year old design... but it's all relative) handgun design.
Another thing to keep in mind when the article goes on about the weakness of the 9mm versus the 45 is that the US Military doesn't use hollow-points.
Take that away and pistol calibers, already quite weak relative to rifle calibers, get even less effective... and in that little-people height contest 45 acp does get further ahead of the 9.