I got another Captain Rex photo in with the other CW photos I got this evening (Space Suit Kenobi, Yoda, 4-A7... Check the front page).
As you can see in this photo, Rex is pretty different. His Range finder appears articulated, and his paintjob's pretty significantly different to previous figures.
I'm pretty sure this is Rex from the 2-packs... But as you can see, pretty significant differences in deco and some changes to the helmet.
Also for your viewing pleasure, a couple new pics of Fives, highlighting his Tattoo and pseudo-goatee.