During the '90s President Clinton signed an Executive Order stating all agencies that issued firearms (under the Executive Branch) were forbidden to sell them, gift them or trade them in in an effort to keep such firearms from entering the commercial market. Agencies could trade and transfer between one another but that was it. Whether subsequent Presidents have kept that policy in force I don't know.
One agency I worked for had a number of very collectible Colt Commando revolvers, some Winchester Model 12 shotguns and a few other odd items. When that agency transitioned from S&W Model 64 revolvers to Sig 9mm pistols…all those older firearms in inventory went to the furnace for destruction. Such a waste of taxpayer money.
If someone was forbidden to keep possession of his father's service revolver…the agency had no choice but to deny it.