I believe this gun, because of it's late 'liberation' from Long Branch could probably be provenance-d through other means than through the family. I think there would likely be some note of disposition on this rifle somewhere, if indeed it came from a place so prominent as a lobby display case at LB. I found a reference to A.Sweeting in some production meeting minutes from August '64, and while not one of the 7 men physically present, he was the first of 15 or so to be cc'd on the minutes. The closing of the Arsenal was a big deal, and there should be something reflected somewhere in official documents. (my $0.02)
But all that speaks only to provenance and value...
What about the led slinger itself?