I, for example, was automatically accepted to the Naval Nuclear Power school, prior to actually hitting boot-camp. Of course, there were no guarantees that I'd graduate (which I did), just that I would get to the school... So yeah, it's possible.
But considering how stupid and stubborn he is, I highly doubt he'll make it to the Rangers- they want people who can think on their feet, not be simple cannon-fodder, like this clown is....
FReegards,