Tell the BATF they need to put a space betw pen and gun,,thats a direct swipe from their NFA Guide Book.
I failed English in HS so what do I know!
There were lots of disguised firearms around at one time. Cig Lighter guns were not hard to find at one time, usually 22rf single shot.
Even the somewhat common wallet holster became an AOW if possessed with the pistol it fit,, and the pistol can be fired while in the holster. It fits under a disguised firearm description.
As far as 'antique' status of NFA firearms,,again from the poor English version of the NFA Handbook:
(Remember that NFA deffinitions are slightly different than GCA deffinitions when it comes to 'firearm'
Ammunition availability is a factor as is Original mfg date. Repro cartridge copys of pre-1899 firearms do NOT qualify)
Section 2.2 Antique firearm. Firearms defined by the NFA as “antique firearms” are not subject to
any controls under the NFA.22 The NFA defines antique firearms based on their date of manufacture
and the type of ignition system used to fire a projectile. Any firearm manufactured in or before 1898
that is not designed or redesigned for using rimfire or conventional center fire ignition with fixed
ammunition is an antique firearm. Additionally, any firearm using a matchlock, flintlock, percussion
cap or similar type ignition system, irrespective of the actual date of manufacture of the firearm, is also
an antique firearm.
NFA firearms using fixed ammunition are antique firearms only if the weapon was actually
manufactured in or before 1898 and the ammunition for the firearm is no longer manufactured in the
United States and is not readily available in the ordinary channels of commercial trade. To qualify as an
antique firearm, a fixed cartridge firing NFA weapon must meet both the age and ammunition
availability standards of the definition.
Concerning ammunition availability, it is important to note that a specific type of fixed ammunition that
has been out of production for many years may again become available due to increasing interest in
older firearms. Therefore, the classification of a specific NFA firearm as an antique can change if
ammunition for the weapon becomes readily available in the ordinary channels of commercial trade.
Here's a link to the entire handbook:
National Firearms Act Handbook | Bureau of Alcohol, Tobacco, Firearms and Explosives