I was told in 1986 by a senior National Park Service Ranger that at the time of Kennedy's death, he had one of the finest collections of Civil War weapons in the world. Springfield Armory had even built a Spencer carbine for presentation to him.
After his death, the NPS tried to acquire the collection, but the Kennedy family refused to acknowledge that it existed.
I suspect that most of this collection is still sitting in a vault somewhere, and will eventually surface over time.
Mike