Is this really all that hard to believe? I don't expect a gun company marketing dept. (or whatever contractor they might hire) to know anything about Lon Horiuchi, except for the law enforcement credentials he gave them.
Or is it customary to google these people, or do a background check, before you put their endorsement ALL OVER the back of your catalog? Which, now that I think about it, makes perfect sense.
The first hit I got when I googled him was the Wiki entry, which basically says, "He's an FBI sniper who got in hot water for killin' a chick at Ruby Ridge, and may have shot some people at Waco." I wouldn't be accepting any endorsements from him, after reading that.