What's the difference between the two?

PRE BAN (Polytech legend Milled receiver AK-47 with all "evil features")



POST BAN (Norinco stamped receiver AK-47 with all featured removed - Thanks Bubba )

Any questions?

As pointed out, the differences would basically be what was done to the rifle to make it legal after that ban.

The "pre-ban" rifles will retain all the normal features intact:
*  bayonet lug or underfolding spike bayonet assembly
*  threaded muzzle
*  military style buttstock and pistol grip
*  straight-cut on the back end of the receiver

The "post-ban" rifles (MAK-90's) will have those normal features removed or neutured:
*  bayonet lug or underfolding spike bayonet assembly cut-off or filed down
*  threads on muzzle turned down to smooth or a muzzle cap tack-welded on
*  "thumbhole" style buttstock with no individual pistol grip
*  often times the straight-cut on the back end of the receiver cut on a slanted angle to prevent the military style buttstock from a solid fit.

In addition to what's already been described, several hundred $.

Also if you start removing ban-style features on a MAK, you then have to make the entire gun 922r compliant.

Is there a pre ban MAK 90?

Technically no.  But the MAK-90 is the same rifle as the pre-ban Norinco 56s just with the evil stuff removed so it could still be imported.

Some pre ban Chinese AK's were on the boat to the US when the ban came into effect, so the importer had to remove the evil features, & remark the guns to "MAK 90" so they could be sold. Some were underfolders, so the folding stocks were removed, the holes plugged, & MAK buttstock attached.  GARY  N4KVE

Isn't this where the NHM series came from?

I have wondered about the NHMs.  I have an NHM-90 that is very similar to my stamped MAK-90, with the exception that it still has a threaded muzzle (with a protector tack welded on) and the FSB still has the detent pin and spring.  I've never seen a MAK like this so I thought that maybe the NHM was either already here or on the way and they just tack welded the protector on to cover the threads.