R7000

> what is the difference between original R7000 and R7000 100NAS

   I'd say that "R7000-100NAS" is the SKU for an R7000[v1] with standard
packaging for North America.

   There's some evidence that the manufacturer replaced the original
detachable antennas with permanently attached antennas, without changing
any of the numbers.

   Why?  Is there some actual problem which you are trying to solve?

> Model: R7000P|Nighthawk AC2300 Smart WiFi Dual Band Gigabit Router

   "R7000P" is different from "R7000".