Hi,
according to this thread, its not, at least the rendered resolution is not the nativ resolution. But the picture is allways rendered bigger to surpress black corners at the edge if you turn your head before the next picture is rendered. You can see that on the loading screen. The rendering stops but the tracking is still working. If you now start thinking about the roll axis, the pixels of the rendered picture will never match exectly the pixels of the vr headset. I would guess that rendering the picture and finemovement of the tracking is decoupled from each other to suppress motion sickness.
https://forums.oculusvr.com/community/discussion/51256/pixel-density-examples
greetings
Merlin