You must be psychic. I was just now thinking about that. I was stuck in traffic today listening to the procession on the radio, and I never did hear it. I heard only band music and the ABC radio commentators droning on and drowning it out.
I was 5 years old in 1963, but still remember watching Kennedy's procession on TV. And, the haunting sound of that single muffled drum was what I remember most clearly.
The muffled drum and more shots of the riderless horse were definitely more dramatic.
Although the horse was just as "there" so I guess it was the camerman who failed to show it as much. Beautiful horse, too.