Sorry,, John, but I loused up my Time Line in my initial response.
The Allies went into Sicily as "Operation Husky", 10 July 43, meaning that they had cleared North Africa and were about to course up the boot of Italy,once Sicily was cleared of the Germans.
My reference states the following limited sequence for Sept-43:
Italian Front: 5 Sept 43, the forces for "Operation Avalanche",for the landing at Salerano, sail from North Africa for Italy; 8 Sept 43,Italy surrenders; 9 Sept 43, Allied troops land at Salerno, the drive north has begun.
I recall that some elements of our (USA) troops were overrun and captured as they entered the early phase of this operation, but I can't recall exactly who/where/when. When I come up with the information, I will route it to you.
I am unable to identify your "191st Battalion". It does not appear in any units identified in Stanton's "WW II Order of BATTLE". There is a listing for 91st Armored Field Artilery Battalion, an element of 1st A/D, which is the only 'close' unit I can ID.
Do you have any other information we could draw on ?