Based on the "lack of markings" referred to in the article, it sounds to me like he was importing older collector type guns and failing to mark them with his name as the importer. Prior to the 68 GCA no markings were required, so if say a WWII issued S&W Victory Model were to show up with no importer's stamp on it, the assumption would be a pre-68 import and more value due to the lack of the stamp. Two identical guns in the case, one with and one without an importer mark, could mean a several hundred dollar price difference. Nowhere did they say they lacked serial numbers, just "required markings possibly to avoid high import taxes and make them more valuable".
Sounds like he was buying guns in Canada and either smuggling them back into the USA, or did the paperwork but failed to stamp them properly before he sold them.
ALL VERY POSSABLE . AN IF HE WAS DOING THIS THEY HAD A REASON TO BUST HIM.
WOULD BE NICE TO SEE SOME PICTURES.
Depending on what kind of "collector" he was, antique guns often don't have serial numbers. I have two Ross rifles with no serial numbers; their military ID numbers were stamped into the original wooden stocks, which are long gone.
edit: and I get to the end of the thread, and CK has said basically the same thing...
YEAP I HAVE SEEN SOME OLD SAVAGE SHOT GUNS WITH NO NUMBERS .
FROM THE SOUNDS OF THE STORY IT DOSENT SOUND LIKE HE WAS COLLECTING ANTIQUES. ALSO IF THEY WERE ANTIQUES THEY WOULD HAVE REASON TO BUT HIM AS ITS NOT AGAINST THE LAW TO HAVE THEM. AGAIN WE HAVE VERY FEW FACTS.
THE KERNELS POINTS ABOUT THEM NOT HAVING IMPORTERS MARKS MAKES SENCE ESPECAILY WHEN THE STORY MAKES MENTION OF THEM BEING THAT WAY TO INCREASE VALUE. WISH MY M1 CARBINE WASENT STAMPED BLUE SKY OR WHATEVER IS ON IT .