Django,
I scanned a few "Statistical Summaries of Combat Operations" when Elly and I were at AFHRA a few years ago, and the August 14/15 mission was one of the records we copied. A gentleman who was with the 331st Bomb Group (one of the 315th Wing Groups) told me several years ago that they had had a quite nice party on the 13th only to get the airplanes cocked for a mission on the 14th. He said he was glad to be a ground crewman for that one, that a lot of his Squadron mates that had to fly probably had some BIG headaches!

My 331st friend thought that "The Uninvited" was the last airplane to drop but that it was entirely possible that it could have been "Horrible Monster". He didn't really care, the war was over, and they could have another party!
I finally found a hardbound copy of Jim Smith's excellent "The Last Mission", and it had much of the same information as I'd heard earlier, but from the 502nd Bomb Group point-of-view. I get a warm feeling knowing that I have walked all over the same AAF stations that Mr. Smith talks about in the early part of his book.
I do have to correct a paragraph in Mr. Smith's book, though--he speaks about being back at Fairmont in 1959 and seeing "the B-29 hangar". In actuality all four hangars that could fit a B-29 are still standing in excellent condition today. The small Squadron hangar on the south end of the apron is the only one missing. Nitpicking, I know, but our friends trying to save the Fairmont history will appreciate it.
In fact, here is a March, 1945 photo of the brand new "flyaway" B-29Bs that the 16th Group flew to Guam after training at Fairmont:
If you look closely you can see the APQ-7 airfoil antenna on 42-63603 and the next airplane in line. Sadly, #603 was lost on 12 July, 1945. This was the sixth 16th Bomb Group mission, and she was being flown by the Berry crew.
Scott