Someday we'll find out it was all fabricated by a bored housewife in Onaga, Kansas. </joke!>
I'm about 98% sure he's the real deal. Too many names, dates, and places check out.
I think you are exactly right. Too much effort being put into using words like s**t and f*** enough to pass off as someone in the military (most people I know use the F word quite frequently but do not write it, that's too much).