The same prop or the same character?
That red and white droid sure seems to get around - Not only does it feature in the ‘Rogue One’ teaser, but I’ve just noticed that’s it’s also in the background of ‘The Force Awakens’ a couple of times too…when Finn arrives at the rebel base, and meets up with Poe again.
(however, the jury’s still out on whether it’s our old friend ‘R5-X2’ from ‘The Phantom Menace’ Jabba scene, or not)