I was just reading up on these yesterday after seeing the Norinco in a catalog. Apparantly it is much stiffer, requires more effort to cycle the weapon than a modern pump. However it is capable of firing rapidly by holding down the trigger and pumping away. Seems like such a technique is potentially dangerous depending, but it was done that way.
Not sure what bayonet it takes, it is a really long one (want to say 03 Springfield but for some reason am thinking Enfield despite it being a foreign issue).
It is a classic and still formidable close combat weapon, and perservered in service for many years, even with the primitive design-exposed hammer, etc.
In the absence of a sidearm a mounted bayonet on a shotgun (whether used as polearm or spear, or both) is an excellent weapon and I could not think of anything with more devastating potential, or reliability, than the combination for close range battle.
The 590 does not have the history but might be a better choice for actual use. If no other reason than quality of manufacture. Scattergun Tech before becoming part of Wilson made a good looking, solid 870 Trench Gun called the Military Model.