My father in law was at the same place/same time after trekking through North Africa.
He told me he and a friend heard that Benito was hanging out at a certain location, and they proceeded to go to see the spectacle. They were previously instructed to avoid the area that they would have to pass through, as it was not safe. As they proceeded, they passed German units that had surrendered, but still had weapons. When they saw what they would have to pass through, they turned around and went back to their unit.
So, my father in law was there, probably 27 years old, but did not get to see il Duce.
We have dad's photos of the partisani (waving from the back of an ox-cart, sitting around drinking wine) - he took a bunch of photos of Mussolini & Co. but we can't find the negatives. >-<