The "class 3" is a type of firearms dealer's license.
If you want to get really technical, the dealer needs a Type 1 or Type 2 FFL, and he needs to pay a Class 3 SOT. A full-auto rifle is a Title 2 weapon, and the purchaser has to send a tax in with a Form 4.
Also, the weapons available for civilian purchase aren't really AK-47's. They're sporter versions of the AKM
. The AK-47 had a milled receiver instead of stamped sheet metal.
Do I expect a politician to know that, or to care, when all he's looking for is a convenient soundbyte to appease his base? Nope. The general public just knows "AK-47."