Actually "1st Lt" is the correct abbreviation. It is the Army that uses "1LT."
That doesn't mean the documents are genuine. The correct abbreviation for lieutenant colonel is "Lt Col" (no periods), not "Lt. Colonel." And the 147th Fighter Interceptor Group is "147 FIG."
The documents have serious, serious problems.
In the Army, the signature on a letterhead document would be "Commanding" not "Commander." True for the Air Force?
Compare the alleged Memo/Order with one of Kerry's orders from his own website, which is typical of the format I saw in the Army, adjusting for service differences. Note the different typeface and format. http://www.johnkerry.com/pdf/jkmilservice/Bupers_Orders_To_Gridley.pdf