I don’t think we will ever know for sure. All I know is my second package had my name and address crossed out in black magic marker and they were attempting to RTS it when I claimed it. Ten minutes more and it would have been gone. It wasn’t Customs that crossed it out at my nearby sorting center. It was USPS that did it.
The word now is it wasn’t customs but USPS that sent them back. The shipper sent them soft wrapped in bags and USPS felt the pistol grips inside so sent them back like it was a gun. The shipper is boxing all the returns for reshipment.
Yes, Customs sent back a bunch of them but a few squeaked through. You just have to be willing to gamble.
They will fit but you have to use their tube in your receiver.
The reason that guy “needs” a heat shield is that he flips the gun over and lays the barrel on his shoulder to reload. That is not an approved technique.