When the Pardner Pump first came out I contacted NEF to find out more info. The gentleman I spoke to was polite and seemed enthusiastic about it. He said it was copied from the 870 as much as possible without infringing on copyright laws. He added that although it was made in China. It is sent back to the states disassembled so that it can be inspected and assembled here. At the time I called he said the first shipment had been sold out and they were waiting for additional shipments. He added that the 870 is considered one of the finest pump shotguns ever made and NEF didn't want the re-invent the wheel, they just wanted to offer their customers a decent pump shotgun and a reasonable price.
By the way, the 2006 H&R/NEF catalog shows that the Pardner pump has been redesigned. It has a small hump at the rear of the reciever like the semi-auto they sell. Also looks a bit like the Mosseberg 535. I think it now can shoot 3 1/2 inch shells.
I'm not sure if parts are interchangeable.
Hope this helps a little.
EVOC ONE