Orbi RBK53 latest hardware

Planning to purchase the Orbi RBK53 mesh system, and would like to order today, if I can. (I have a couple of days off work this coming week to work on set-up.)

I have a few outstanding questions posted yesterday, but will take these as it comes, I think. 

Checking with various vendors, hardware identification is unclear. I simply need to figure out how to tell if I'm buying the latest hardware.

Netgear website indicates a version 2, noted: 

RBR50v2   (router)

RBS50v2   (satellites)

I've not found these model numbers on Amazon or any other vendors!

Seeing RBK53S-100NAS on more than one source

Also finding RBK53S and RBK535 on Amazon vendors now.

I am confused by these varied designations.

Any clarification will be much appreciated. Thanks!