What's the difference among polish,EG and Russian PPN2/NSP2?

Don't know myself, but perhaps @TX-Zen might be able to shed some light on it for you.

I have a few cold war era NV optics but they are not my main area of expertise. Those listed were probably manufactured in their respective countries and have a face plate that shows that. I am not aware of any detailed differences between them

As a general statement I have found Polish to have better performance (for 1PN34 and 1PN58) which is probably due to the Polish devices being much newer and with way less hours of use than the clearly older soviet models I've had

Dragunov.net probably has better info, and Brian Wilhelm of theakforum.net probably has the PPN-2 if you can locate him