Hi, Chris. I am familiar with the guns in Col. Gideon's collection, and the JAM gun is not part of that collection. As you may know, Col. Gideon was a long time collector of Detonics firearms, and his collection includes many unusual pieces, including a couple of shortened Combat Masters with conventional serial numbers. I confirmed with another former Detonics employee that neither of those guns are the gun your father put together. Col. Gideon bought and sold guns as part of his collecting, but I have not seen any indication the JAM serial numbered gun ever was part of his collection or what might have happened to it.