Sam most definitely was, and he continued what began in his letters home and WWII personal journals in USS STEVENS, and then to TWO graphic novels for Marvel before they folded the graphic novel line.
Others arguably drew on/from their experiences, but not as explicit autobiography; even USS STEVENS wasn't presented per se as Sam's experiences, though his Marvel graphic novels were.
There were a number of soldier cartoonists who produced published work throughout WWI and WWII, and the military papers sported an abundance of cartoons by G.I.s, up to and including the Vietnam War era. The mainstream comics publishers and underground comix publishers didn't embrace these, save for out-and-out humor strips like SAD SACK (which Harvey ran as a comicbook series for decades). Post-Vietnam, though, we've another breed in the direct sales market -- Don Lomax's VIETNAM JOURNAL comes to mind, in this context.