Chances are that he paid his $200 and endured the 8-12 month background check in order to get his tax stamp for it.
If he had obtained it illegally or had fabricated it, that would have been shouted from the rooftops by the MSM. But if he successfully underwent a background check, that undermines their argument for 'universal background checks,' so all you'll hear from the MSM are crickets.
But one would think that the ATF might have come out almost immediately with information about the device, considering all of them legally owned are registered. Wouldn’t be difficult to find out if it was legal or not.
At least, the ATF might want to cover their butts with the data.
To show the public that they’re doing their jobs.