lowercase is correct. Keywords are "other than". If one were to just go to the ATF's website, it would: say the following
Q: May a nonlicensee ship a firearm by common or contract carrier?
A: nonlicensee may ship a firearm by a common or contract carrier to a resident of his or her own State or to a licensee in any State. A common or contract carrier must be used to ship a handgun. In addition, Federal law requires that the carrier be notified that the shipment contains a firearm and prohibits common or contract carriers from requiring or causing any label to be placed on any package indicating that it contains a firearm.
[18 U.S.C. 922(a)(2)(A), 922(a) (3), 922(a)(5) and 922(e), 27 CFR 478.31 and 478.30]
HOWEVER, the statute is...
(e) It shall be unlawful for any person knowingly to deliver or cause to be delivered to any common or contract carrier for transportation or shipment in interstate or foreign commerce, to persons other than licensed importers, licensed manufacturers, licensed dealers, or licensed collectors, any package or other container in which there is any firearm or ammunition without written notice to the carrier that such firearm or ammunition is being transported or shipped; except that any passenger who owns or legally possesses a firearm or ammunition being transported aboard any common or contract carrier for movement with the passenger in interstate or foreign commerce may deliver said firearm or ammunition into the custody of the pilot, captain, conductor or operator of such common or contract carrier for the duration of the trip without violating any of the provisions of this chapter. No common or contract carrier shall require or cause any label, tag, or other written notice to be placed on the outside of any package, luggage, or other container that such package, luggage, or other container contains a firearm.
Take out the blue text and it becomes what so many individuals believe. I recall someone on TFL pointing this out to me a while back. Up until that point, I thought it was a violation of Federal Laws to ship a firearm to a FFL using a common carrier w/o informing them that the package contains a firearm and paying overnight shipping, instead of UPS Ground or something less expensive. The main caveat is the gun's value and insurability. For something like an Armscor M200, I'd use UPS Ground with Tracking & Adult Signature Required and not overnight.
Going back to the OP's Armscor, just send it back to the factory. They will fix it and send it back to you. No need to kitchen table smith it. It'll cost you about $15 total.
"With great power, there must also come great responsibility." - Stan Lee
"All that is necessary for evil to triumph is for good men to do nothing." - Edmund Burke