Yes - normal gun paperwork with the NICS background check. They will simply be treated as a firearm - normal age restrictions, normal purchase process. No $200 tax stamp, no more 6-12 month wait, not part of NFA.

As for the oil filter... it will probably "not be illegal" until someone figures that out. Like the printed guns or 80% lowers. Some places made them illegal, some didn't. The feds keep trying. It's all a game.

Personally I can't wait for all the morons to buy them, realize they don't work like in the movies, and demand a refund because they are "defective". That's when the prices will stabilize.