Gents- you are both correct. A holster that conceals the appearance of a firearm, AND permits the gun to be fired while still concealed is an NFA Any Other Weapon.
An example made a few years back look like a wallet, with a round hole cut in one side. Wrapped completely around a Hi Standard 22 Magnum derringer- and allowed you to fire it by sticking your finger into the hole. while pistol was still wrapped up in holster.