On Friday night Michael Bane told me that BATFE visited the Taurus booth at SHOT Show and declared that the 28 gauge revolver was in fact a SBS (Short Barreled Shotgun), not a handgun.
Taurus USA imports their pistols from the Taurus factory in Brazil. If they were imported the sample 28 gauge SBS and specified in the US Customs / BATFE paperwork that is was a pistol, they could be in trouble.
I contacted the Taurus PR but I have not yet received a reply.
UPDATE: According to Taurus PR this information is apparently not correct.