All of the vehicles show significant amount of wear&tear, actually, and that was seen way before the current reveal - the wheels and tracks definiteky had hundreds of miles traveled (in case of some, likely thousands).
The reason is simple: they are all prototypes which have undergone lots of...
Well. tank radars need not to be that big anymore; for decent mm- or cm- wave radar detection of threats at about 200 meters, an AESA radar could be really very small.
And there were news that Armata gets 26-40 GHz AESA radars more than an year ago - and they can be seen on photos.
500> it's actually a different thing
niistali[.]ru/products/nauka/protection/uplook_protection/
The up-facing grenade launchers that can be seen on both T-14 and T-15's rear are parts of this system, containing lots of IR-masking aerosol, flares and chaff (and reportedly EMP charges). That's...