If you know that much it might be worth your time to pay a researcher at the National Achieves to get you copies of the battalion after action reports for the period in question. These are usually still available. They may give you a clue to exact operations and possibly even mention names of personnel you might be able to contact through a veteran's group.
Oh, on the medals: GO is "General Order" and WD is War Department. Basically, on the campaign medals a general order by the war department is issued stating something like "Everybody that was in this particular theater, operation, whatever, between date A and B is entitled to wear the Something or Other Campaign medal." I have gotten a couple of these awards. Unit awards are similar in nature.
You might also find this interesting:
New WW II APO Book Now Available