Are all oilless PCP pumps on amazon the same?

I picked up a cheap no-name compressor from amazon last may for $168. Its works really well and looks well made. The power supply went out in it recently but that was an easy fix as those power supplies are sold on amazon as well.

I looked at other pumps to see what's out there and it looks like they are actually all the same pump; at least mechanically. The cases are different, but they sound the same and sometimes these pumps have louvers over the pumping assembly, and you can clearly see its the same assembly behind them.

Here was the model i bought,
no longer sold, but you can tell all of these looks very similar.
I did find a specialty air gun store selling the same model pump for $400, seems like marketing at its best. I think the CS3 is the same pump as well.
I think there is one Chinese company producing the mechanicals for these.
 
Agreed, oil-less, waterless, multi-power, high-speed-fan only cooled rectangular box quick-fill compressors are alike. Expected lifetime is 12-18 months with limited rebuild success. Manufacturers support, "discard, buy another," versus, "rebuild/repair." The GX-CS compressor series differs significantly in that lower gearing, slower fill operation reduces compressor-killing heat while grease-injection and water-cooling are available in some models. GX-CS also supports, "repair/rebuild," over, "discard, buy another." WM