Nope, it's still all available ('cept post-'86 MGs). You can get the go-boom stuff, it's just that you have to pay the $200 tax on each round. Ok, so that turns in to a practical ban...which was the point of NFA in the first place (ex.: $200 tax on a $5 MG in 1935). Only reason we tolerate NFA now is that inflation over 70+ years has brought the value of $200 down to a tolerable tax on good quality stuff (and comparably, the taxed stuff has risen in quality to warrant such prices - suppressors shouldn't be $1000, but if you're going to pay $200 tax on one you might as well get something really quiet and indestructable). If the tax had been indexed to inflation, we'd have gotten a case to SCOTUS overturning NFA already.
Also, I need to make a correction to part of my earlier statement. Taking a look around, it turns out the Remington 870MKS is considered an AOW (All Other Weapons) and only requires a Form 4 and a $5 tax. However, it's expensive and Knights Armament won't sell 'em to just anyone. I've only found one person for far that says they were able to purchase one.