You won't get an answer to that question from the Inspector General. His job is to investigate compliance with regulations, not interpret them for the general public. In other words, he responds to complaint forms only.
The answer to your question is in the Post Office regulations manual. You need to assert on the claim form that a specific individual, by name, did violate a given paragraph in that manual on a specific data at a specific time.
They don't make it easy.
The definition of an antique firearm is in the Domestic Mail Manual (DMM) 601 Section 12 paragraph 12.1.1 g:
Quote:
Antique firearm means any firearm (including those with a matchlock, flintlock, percussion cap, or similar type of ignition system) manufactured in or before 1898, or any replica thereof, if such replica:
1. Is not designed or redesigned for using rimfire or conventional centerfire fixed ammunition.
2. Uses rimfire or conventional centerfire fixed ammunition that is no longer manufactured in the United States and that is not readily available in the ordinary channels of commercial trade.
The mailability of antique firearms is proscribed in DMM 601 Section 12 paragraph 12.2:
Quote:
Antique Firearms
Antique firearms sent as curios or museum pieces may be accepted for mailing without regard to 12.1.3 through 12.1.6.
(The referenced paragraphs 12.1.3 through 12.1.6 describe conditions under which certain authorized persons may mail otherwise prohibited guns).
Postal Service employees may not ask a customer what is in the package. The only question they are allowed to ask is whether the package contains anything that is hazardous, perishable or restricted. An antique firearm is considered a restricted item, so if asked that question you must answer yes. However, that's all you need to do. They still cannot ask specifically what the restricted material is. Your answer to the question tells them how to route the item (air transportation, for instance, is not allowed for restricted items) but that's all they need to know.