Heya, Wild Geese!
The Chinese Type 56 Assault Rifle, not to be confused with the Type 56 Rifle (a copy of the Soviet SKS), is a copy of the Soviet AK-47 and later AKM assault rifles. Early production Type 56's used a milled receiver like the AK-47, where later production Type 56's use a sheet metal receiver like the improved AKM. Key recognition points are the fully hooded front sight (original Soviet design is open topped, like the letter "U"), and typically a non-detachable folding spike bayonet.
Picture shows an early Type 56 top and a Soviet AKS-47 bottom. Note on both rifles the long cut-out right below the ejection port... this is the lightening cut made on milled receivers. Also, note the difference between the front sight of the two weapons (kinda hard to tell). Both weapons also have a plain barrel nut at the muzzle.
Here is a link to a large picture showing a PLAN sailor armed with a late Type 56. Weapon has no barrel nut / plain muzzle, and no lightening cut on receiver. This is a stamped metal receiver.
This picture shows two Soviet weapons, an AKMS top (folding stock variant of improved AKM) and an early AK-47 bottom. Note on the AKMS the small dimple below the ejection port... this is indicative of a stamped metal receiver. Some Chinese copies have this, some don't. The lower weapon shows the lightening cuts on a milled steel receiver.
The lower forward handguard of Chinese manufactured weapons almost always (99.999% of the time) has a slot cut into the bottom of it for a spike bayonet to fold into, even if the weapon doesn't have a spike bayonet fitted to it.
Here is a picture of a Soviet / Russian AKM showing the slanted barrel nut that acts as a rudimentary compensator. As this just screws onto a threaded barrel, it can be seen on old and new weapons.
The picture also shows the AKM type bayonet that can attach to it sheath and function as a wire cutter. Some late Chinese weapons, probably mainly for export, had a copy of this bayonet.
For the non-mechanically inclined: a milled receiver, like on the AK-47, starts life as a block of steel. Machining operations mill, drill, bore and ream material away until the 8 pound or so block is cut down to 2 pounds. Milled receivers are generally stronger, but weigh more and require extensive (and expensive) machining equipment. A stamped receiver starts out as a flat steel plate, around a 1/16th of an inch thick. Machinery stamps out the rough shape, a finished shape, holes, etc. The piece is then bent to a box shape, and reinforcements and such are added. Stamped receivers are lighter, but not quite as durable as milled receivers.
Hope this helps!
Proud son of Rose and Wes